--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -1,3338 +1,3338 @@
-/* vi:set ts=8 sts=4 sw=4 noet:
- *
- * VIM - Vi IMproved	by Bram Moolenaar
- *
- * Do ":help uganda"  in Vim to read copying and usage conditions.
- * Do ":help credits" in Vim to see a list of people who contributed.
- * See README.txt for an overview of the Vim source code.
- */
-
-/*
- * optionstr.c: Functions related to string options
- */
-
-#include "vim.h"
-
-static char_u shm_buf[SHM_LEN];
-static int set_shm_recursive = 0;
-
-static char *(p_ambw_values[]) = {"single", "double", NULL};
-static char *(p_bg_values[]) = {"light", "dark", NULL};
-static char *(p_bkc_values[]) = {"yes", "auto", "no", "breaksymlink", "breakhardlink", NULL};
-static char *(p_bo_values[]) = {"all", "backspace", "cursor", "complete",
-				 "copy", "ctrlg", "error", "esc", "ex",
-				 "hangul", "insertmode", "lang", "mess",
-				 "showmatch", "operator", "register", "shell",
-				 "spell", "term", "wildmode", NULL};
-static char *(p_nf_values[]) = {"bin", "octal", "hex", "alpha", "unsigned", NULL};
-static char *(p_ff_values[]) = {FF_UNIX, FF_DOS, FF_MAC, NULL};
-#ifdef FEAT_CRYPT
-static char *(p_cm_values[]) = {"zip", "blowfish", "blowfish2",
- # ifdef FEAT_SODIUM
-    "xchacha20", "xchacha20v2",
- # endif
-    NULL};
-#endif
-static char *(p_cmp_values[]) = {"internal", "keepascii", NULL};
-static char *(p_dy_values[]) = {"lastline", "truncate", "uhex", NULL};
-#ifdef FEAT_FOLDING
-static char *(p_fdo_values[]) = {"all", "block", "hor", "mark", "percent",
-				 "quickfix", "search", "tag", "insert",
-				 "undo", "jump", NULL};
-#endif
-#ifdef FEAT_SESSION
-// Also used for 'viewoptions'!  Keep in sync with SSOP_ flags.
-static char *(p_ssop_values[]) = {"buffers", "winpos", "resize", "winsize",
-    "localoptions", "options", "help", "blank", "globals", "slash", "unix",
-    "sesdir", "curdir", "folds", "cursor", "tabpages", "terminal", "skiprtp",
-    NULL};
-#endif
-// Keep in sync with SWB_ flags in option.h
-static char *(p_swb_values[]) = {"useopen", "usetab", "split", "newtab", "vsplit", "uselast", NULL};
-static char *(p_spk_values[]) = {"cursor", "screen", "topline", NULL};
-static char *(p_tc_values[]) = {"followic", "ignore", "match", "followscs", "smart", NULL};
-#if defined(FEAT_TOOLBAR) && !defined(FEAT_GUI_MSWIN)
-static char *(p_toolbar_values[]) = {"text", "icons", "tooltips", "horiz", NULL};
-#endif
-#if defined(FEAT_TOOLBAR) && defined(FEAT_GUI_GTK)
-static char *(p_tbis_values[]) = {"tiny", "small", "medium", "large", "huge", "giant", NULL};
-#endif
-#if defined(UNIX) || defined(VMS)
-static char *(p_ttym_values[]) = {"xterm", "xterm2", "dec", "netterm", "jsbterm", "pterm", "urxvt", "sgr", NULL};
-#endif
-static char *(p_ve_values[]) = {"block", "insert", "all", "onemore", "none", "NONE", NULL};
-static char *(p_wop_values[]) = {"fuzzy", "tagfile", "pum", NULL};
-#ifdef FEAT_WAK
-static char *(p_wak_values[]) = {"yes", "menu", "no", NULL};
-#endif
-static char *(p_mousem_values[]) = {"extend", "popup", "popup_setpos", "mac", NULL};
-static char *(p_sel_values[]) = {"inclusive", "exclusive", "old", NULL};
-static char *(p_slm_values[]) = {"mouse", "key", "cmd", NULL};
-static char *(p_km_values[]) = {"startsel", "stopsel", NULL};
-#ifdef FEAT_BROWSE
-static char *(p_bsdir_values[]) = {"current", "last", "buffer", NULL};
-#endif
-static char *(p_scbopt_values[]) = {"ver", "hor", "jump", NULL};
-static char *(p_debug_values[]) = {"msg", "throw", "beep", NULL};
-static char *(p_ead_values[]) = {"both", "ver", "hor", NULL};
-static char *(p_buftype_values[]) = {"nofile", "nowrite", "quickfix", "help", "terminal", "acwrite", "prompt", "popup", NULL};
-static char *(p_bufhidden_values[]) = {"hide", "unload", "delete", "wipe", NULL};
-static char *(p_bs_values[]) = {"indent", "eol", "start", "nostop", NULL};
-#ifdef FEAT_FOLDING
-static char *(p_fdm_values[]) = {"manual", "expr", "marker", "indent", "syntax",
-# ifdef FEAT_DIFF
-				"diff",
-# endif
-				NULL};
-static char *(p_fcl_values[]) = {"all", NULL};
-#endif
-static char *(p_cot_values[]) = {"menu", "menuone", "longest", "preview", "popup", "popuphidden", "noinsert", "noselect", NULL};
-#ifdef BACKSLASH_IN_FILENAME
-static char *(p_csl_values[]) = {"slash", "backslash", NULL};
-#endif
-#ifdef FEAT_SIGNS
-static char *(p_scl_values[]) = {"yes", "no", "auto", "number", NULL};
-#endif
-#if defined(MSWIN) && defined(FEAT_TERMINAL)
-static char *(p_twt_values[]) = {"winpty", "conpty", "", NULL};
-#endif
-static char *(p_sloc_values[]) = {"last", "statusline", "tabline", NULL};
-static char *(p_sws_values[]) = {"fsync", "sync", NULL};
-
-static int check_opt_strings(char_u *val, char **values, int list);
-static int opt_strings_flags(char_u *val, char **values, unsigned *flagp, int list);
-
-/*
- * After setting various option values: recompute variables that depend on
- * option values.
- */
-    void
-didset_string_options(void)
-{
-    (void)opt_strings_flags(p_cmp, p_cmp_values, &cmp_flags, TRUE);
-    (void)opt_strings_flags(p_bkc, p_bkc_values, &bkc_flags, TRUE);
-    (void)opt_strings_flags(p_bo, p_bo_values, &bo_flags, TRUE);
-#ifdef FEAT_SESSION
-    (void)opt_strings_flags(p_ssop, p_ssop_values, &ssop_flags, TRUE);
-    (void)opt_strings_flags(p_vop, p_ssop_values, &vop_flags, TRUE);
-#endif
-#ifdef FEAT_FOLDING
-    (void)opt_strings_flags(p_fdo, p_fdo_values, &fdo_flags, TRUE);
-#endif
-    (void)opt_strings_flags(p_dy, p_dy_values, &dy_flags, TRUE);
-    (void)opt_strings_flags(p_tc, p_tc_values, &tc_flags, FALSE);
-    (void)opt_strings_flags(p_ve, p_ve_values, &ve_flags, TRUE);
-#if defined(UNIX) || defined(VMS)
-    (void)opt_strings_flags(p_ttym, p_ttym_values, &ttym_flags, FALSE);
-#endif
-#if defined(FEAT_TOOLBAR) && !defined(FEAT_GUI_MSWIN)
-    (void)opt_strings_flags(p_toolbar, p_toolbar_values, &toolbar_flags, TRUE);
-#endif
-#if defined(FEAT_TOOLBAR) && defined(FEAT_GUI_GTK)
-    (void)opt_strings_flags(p_tbis, p_tbis_values, &tbis_flags, FALSE);
-#endif
-    (void)opt_strings_flags(p_swb, p_swb_values, &swb_flags, TRUE);
-}
-
-#if defined(FEAT_EVAL) || defined(PROTO)
-/*
- * Trigger the OptionSet autocommand.
- * "opt_idx"	is the index of the option being set.
- * "opt_flags"	can be OPT_LOCAL etc.
- * "oldval"	the old value
- *  "oldval_l"  the old local value (only non-NULL if global and local value
- *		are set)
- * "oldval_g"   the old global value (only non-NULL if global and local value
- *		are set)
- * "newval"	the new value
- */
-    void
-trigger_optionset_string(
-	int	opt_idx,
-	int	opt_flags,
-	char_u  *oldval,
-	char_u  *oldval_l,
-	char_u  *oldval_g,
-	char_u  *newval)
-{
-    // Don't do this recursively.
-    if (oldval == NULL || newval == NULL
-				    || *get_vim_var_str(VV_OPTION_TYPE) != NUL)
-	return;
-
-    char_u buf_type[7];
-
-    sprintf((char *)buf_type, "%s",
-	    (opt_flags & OPT_LOCAL) ? "local" : "global");
-    set_vim_var_string(VV_OPTION_OLD, oldval, -1);
-    set_vim_var_string(VV_OPTION_NEW, newval, -1);
-    set_vim_var_string(VV_OPTION_TYPE, buf_type, -1);
-    if (opt_flags & OPT_LOCAL)
-    {
-	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"setlocal", -1);
-	set_vim_var_string(VV_OPTION_OLDLOCAL, oldval, -1);
-    }
-    if (opt_flags & OPT_GLOBAL)
-    {
-	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"setglobal", -1);
-	set_vim_var_string(VV_OPTION_OLDGLOBAL, oldval, -1);
-    }
-    if ((opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0)
-    {
-	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"set", -1);
-	set_vim_var_string(VV_OPTION_OLDLOCAL, oldval_l, -1);
-	set_vim_var_string(VV_OPTION_OLDGLOBAL, oldval_g, -1);
-    }
-    if (opt_flags & OPT_MODELINE)
-    {
-	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"modeline", -1);
-	set_vim_var_string(VV_OPTION_OLDLOCAL, oldval, -1);
-    }
-    apply_autocmds(EVENT_OPTIONSET,
-	    get_option_fullname(opt_idx), NULL, FALSE,
-	    NULL);
-    reset_v_option_vars();
-}
-#endif
-
-    static char *
-illegal_char(char *errbuf, int c)
-{
-    if (errbuf == NULL)
-	return "";
-    sprintf((char *)errbuf, _(e_illegal_character_str), (char *)transchar(c));
-    return errbuf;
-}
-
-/*
- * Check string options in a buffer for NULL value.
- */
-    void
-check_buf_options(buf_T *buf)
-{
-    check_string_option(&buf->b_p_bh);
-    check_string_option(&buf->b_p_bt);
-    check_string_option(&buf->b_p_fenc);
-    check_string_option(&buf->b_p_ff);
-#ifdef FEAT_FIND_ID
-    check_string_option(&buf->b_p_def);
-    check_string_option(&buf->b_p_inc);
-# ifdef FEAT_EVAL
-    check_string_option(&buf->b_p_inex);
-# endif
-#endif
-#if defined(FEAT_EVAL)
-    check_string_option(&buf->b_p_inde);
-    check_string_option(&buf->b_p_indk);
-#endif
-#if defined(FEAT_BEVAL) && defined(FEAT_EVAL)
-    check_string_option(&buf->b_p_bexpr);
-#endif
-#if defined(FEAT_CRYPT)
-    check_string_option(&buf->b_p_cm);
-#endif
-    check_string_option(&buf->b_p_fp);
-#if defined(FEAT_EVAL)
-    check_string_option(&buf->b_p_fex);
-#endif
-#ifdef FEAT_CRYPT
-    check_string_option(&buf->b_p_key);
-#endif
-    check_string_option(&buf->b_p_kp);
-    check_string_option(&buf->b_p_mps);
-    check_string_option(&buf->b_p_fo);
-    check_string_option(&buf->b_p_flp);
-    check_string_option(&buf->b_p_isk);
-    check_string_option(&buf->b_p_com);
-#ifdef FEAT_FOLDING
-    check_string_option(&buf->b_p_cms);
-#endif
-    check_string_option(&buf->b_p_nf);
-    check_string_option(&buf->b_p_qe);
-#ifdef FEAT_SYN_HL
-    check_string_option(&buf->b_p_syn);
-    check_string_option(&buf->b_s.b_syn_isk);
-#endif
-#ifdef FEAT_SPELL
-    check_string_option(&buf->b_s.b_p_spc);
-    check_string_option(&buf->b_s.b_p_spf);
-    check_string_option(&buf->b_s.b_p_spl);
-    check_string_option(&buf->b_s.b_p_spo);
-#endif
-    check_string_option(&buf->b_p_sua);
-    check_string_option(&buf->b_p_cink);
-    check_string_option(&buf->b_p_cino);
-    check_string_option(&buf->b_p_cinsd);
-    parse_cino(buf);
-    check_string_option(&buf->b_p_lop);
-    check_string_option(&buf->b_p_ft);
-    check_string_option(&buf->b_p_cinw);
-    check_string_option(&buf->b_p_cpt);
-#ifdef FEAT_COMPL_FUNC
-    check_string_option(&buf->b_p_cfu);
-    check_string_option(&buf->b_p_ofu);
-    check_string_option(&buf->b_p_tsrfu);
-#endif
-#ifdef FEAT_EVAL
-    check_string_option(&buf->b_p_tfu);
-#endif
-#ifdef FEAT_KEYMAP
-    check_string_option(&buf->b_p_keymap);
-#endif
-#ifdef FEAT_QUICKFIX
-    check_string_option(&buf->b_p_gp);
-    check_string_option(&buf->b_p_mp);
-    check_string_option(&buf->b_p_efm);
-#endif
-    check_string_option(&buf->b_p_ep);
-    check_string_option(&buf->b_p_path);
-    check_string_option(&buf->b_p_tags);
-    check_string_option(&buf->b_p_tc);
-    check_string_option(&buf->b_p_dict);
-    check_string_option(&buf->b_p_tsr);
-    check_string_option(&buf->b_p_lw);
-    check_string_option(&buf->b_p_bkc);
-    check_string_option(&buf->b_p_menc);
-#ifdef FEAT_VARTABS
-    check_string_option(&buf->b_p_vsts);
-    check_string_option(&buf->b_p_vts);
-#endif
-}
-
-/*
- * Free the string allocated for an option.
- * Checks for the string being empty_option. This may happen if we're out of
- * memory, vim_strsave() returned NULL, which was replaced by empty_option by
- * check_options().
- * Does NOT check for P_ALLOCED flag!
- */
-    void
-free_string_option(char_u *p)
-{
-    if (p != empty_option)
-	vim_free(p);
-}
-
-    void
-clear_string_option(char_u **pp)
-{
-    if (*pp != empty_option)
-	vim_free(*pp);
-    *pp = empty_option;
-}
-
-    void
-check_string_option(char_u **pp)
-{
-    if (*pp == NULL)
-	*pp = empty_option;
-}
-
-/*
- * Set global value for string option when it's a local option.
- */
-    static void
-set_string_option_global(
-    int		opt_idx,	// option index
-    char_u	**varp)		// pointer to option variable
-{
-    char_u	**p, *s;
-
-    // the global value is always allocated
-    if (is_window_local_option(opt_idx))
-	p = (char_u **)GLOBAL_WO(varp);
-    else
-	p = (char_u **)get_option_var(opt_idx);
-    if (!is_global_option(opt_idx)
-	    && p != varp
-	    && (s = vim_strsave(*varp)) != NULL)
-    {
-	free_string_option(*p);
-	*p = s;
-    }
-}
-
-/*
- * Set a string option to a new value (without checking the effect).
- * The string is copied into allocated memory.
- * if ("opt_idx" == -1) "name" is used, otherwise "opt_idx" is used.
- * When "set_sid" is zero set the scriptID to current_sctx.sc_sid.  When
- * "set_sid" is SID_NONE don't set the scriptID.  Otherwise set the scriptID to
- * "set_sid".
- */
-    void
-set_string_option_direct(
-    char_u	*name,
-    int		opt_idx,
-    char_u	*val,
-    int		opt_flags,	// OPT_FREE, OPT_LOCAL and/or OPT_GLOBAL
-    int		set_sid UNUSED)
-{
-    char_u	*s;
-    char_u	**varp;
-    int		both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
-    int		idx = opt_idx;
-
-    if (idx == -1)		// use name
-    {
-	idx = findoption(name);
-	if (idx < 0)	// not found (should not happen)
-	{
-	    semsg(_(e_internal_error_str), "set_string_option_direct()");
-	    siemsg("For option %s", name);
-	    return;
-	}
-    }
-
-    if (is_hidden_option(idx))		// can't set hidden option
-	return;
-
-    s = vim_strsave(val);
-    if (s == NULL)
-	return;
-
-    varp = (char_u **)get_option_varp_scope(idx,
-	    both ? OPT_LOCAL : opt_flags);
-    if ((opt_flags & OPT_FREE) && (get_option_flags(idx) & P_ALLOCED))
-	free_string_option(*varp);
-    *varp = s;
-
-    // For buffer/window local option may also set the global value.
-    if (both)
-	set_string_option_global(idx, varp);
-
-    set_option_flag(idx, P_ALLOCED);
-
-    // When setting both values of a global option with a local value,
-    // make the local value empty, so that the global value is used.
-    if (is_global_local_option(idx) && both)
-    {
-	free_string_option(*varp);
-	*varp = empty_option;
-    }
-# ifdef FEAT_EVAL
-    if (set_sid != SID_NONE)
-    {
-	sctx_T script_ctx;
-
-	if (set_sid == 0)
-	    script_ctx = current_sctx;
-	else
-	{
-	    script_ctx.sc_sid = set_sid;
-	    script_ctx.sc_seq = 0;
-	    script_ctx.sc_lnum = 0;
-	    script_ctx.sc_version = 1;
-	}
-	set_option_sctx_idx(idx, opt_flags, script_ctx);
-    }
-# endif
-}
-
-#if defined(FEAT_PROP_POPUP) || \
-    (defined(FEAT_DIFF) && defined(FEAT_FOLDING)) || defined(PROTO)
-/*
- * Like set_string_option_direct(), but for a window-local option in "wp".
- * Blocks autocommands to avoid the old curwin becoming invalid.
- */
-    void
-set_string_option_direct_in_win(
-	win_T		*wp,
-	char_u		*name,
-	int		opt_idx,
-	char_u		*val,
-	int		opt_flags,
-	int		set_sid)
-{
-    win_T	*save_curwin = curwin;
-
-    block_autocmds();
-    curwin = wp;
-    curbuf = curwin->w_buffer;
-    set_string_option_direct(name, opt_idx, val, opt_flags, set_sid);
-    curwin = save_curwin;
-    curbuf = curwin->w_buffer;
-    unblock_autocmds();
-}
-#endif
-
-#if defined(FEAT_PROP_POPUP) || defined(PROTO)
-/*
- * Like set_string_option_direct(), but for a buffer-local option in "buf".
- * Blocks autocommands to avoid the old curbuf becoming invalid.
- */
-    void
-set_string_option_direct_in_buf(
-	buf_T		*buf,
-	char_u		*name,
-	int		opt_idx,
-	char_u		*val,
-	int		opt_flags,
-	int		set_sid)
-{
-    buf_T	*save_curbuf = curbuf;
-
-    block_autocmds();
-    curbuf = buf;
-    curwin->w_buffer = curbuf;
-    set_string_option_direct(name, opt_idx, val, opt_flags, set_sid);
-    curbuf = save_curbuf;
-    curwin->w_buffer = curbuf;
-    unblock_autocmds();
-}
-#endif
-
-/*
- * Set a string option to a new value, and handle the effects.
- *
- * Returns NULL on success or an untranslated error message on error.
- */
-    char *
-set_string_option(
-    int		opt_idx,
-    char_u	*value,
-    int		opt_flags,	// OPT_LOCAL and/or OPT_GLOBAL
-    char	*errbuf)
-{
-    char_u	*s;
-    char_u	**varp;
-    char_u	*oldval;
-#if defined(FEAT_EVAL)
-    char_u	*oldval_l = NULL;
-    char_u	*oldval_g = NULL;
-    char_u	*saved_oldval = NULL;
-    char_u	*saved_oldval_l = NULL;
-    char_u	*saved_oldval_g = NULL;
-    char_u	*saved_newval = NULL;
-#endif
-    char	*errmsg = NULL;
-    int		value_checked = FALSE;
-
-    if (is_hidden_option(opt_idx))	// don't set hidden option
-	return NULL;
-
-    s = vim_strsave(value == NULL ? (char_u *)"" : value);
-    if (s == NULL)
-	return NULL;
-
-    varp = (char_u **)get_option_varp_scope(opt_idx,
-	    (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0
-	    ? (is_global_local_option(opt_idx)
-		? OPT_GLOBAL : OPT_LOCAL)
-	    : opt_flags);
-    oldval = *varp;
-#if defined(FEAT_EVAL)
-    if ((opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0)
-    {
-	oldval_l = *(char_u **)get_option_varp_scope(opt_idx, OPT_LOCAL);
-	oldval_g = *(char_u **)get_option_varp_scope(opt_idx, OPT_GLOBAL);
-    }
-#endif
-    *varp = s;
-
-#if defined(FEAT_EVAL)
-    if (!starting
-# ifdef FEAT_CRYPT
-	    && !is_crypt_key_option(opt_idx)
-# endif
-       )
-    {
-	if (oldval_l != NULL)
-	    saved_oldval_l = vim_strsave(oldval_l);
-	if (oldval_g != NULL)
-	    saved_oldval_g = vim_strsave(oldval_g);
-	saved_oldval = vim_strsave(oldval);
-	saved_newval = vim_strsave(s);
-    }
-#endif
-    if ((errmsg = did_set_string_option(opt_idx, varp, oldval, value, errbuf,
-		    opt_flags, &value_checked)) == NULL)
-	did_set_option(opt_idx, opt_flags, TRUE, value_checked);
-
-#if defined(FEAT_EVAL)
-    // call autocommand after handling side effects
-    if (errmsg == NULL)
-	trigger_optionset_string(opt_idx, opt_flags,
-		saved_oldval, saved_oldval_l,
-		saved_oldval_g, saved_newval);
-    vim_free(saved_oldval);
-    vim_free(saved_oldval_l);
-    vim_free(saved_oldval_g);
-    vim_free(saved_newval);
-#endif
-    return errmsg;
-}
-
-/*
- * Return TRUE if "val" is a valid 'filetype' name.
- * Also used for 'syntax' and 'keymap'.
- */
-    static int
-valid_filetype(char_u *val)
-{
-    return valid_name(val, ".-_");
-}
-
-#ifdef FEAT_STL_OPT
-/*
- * Check validity of options with the 'statusline' format.
- * Return an untranslated error message or NULL.
- */
-    static char *
-check_stl_option(char_u *s)
-{
-    int		groupdepth = 0;
-    static char errbuf[80];
-
-    while (*s)
-    {
-	// Check for valid keys after % sequences
-	while (*s && *s != '%')
-	    s++;
-	if (!*s)
-	    break;
-	s++;
-	if (*s == '%' || *s == STL_TRUNCMARK || *s == STL_SEPARATE)
-	{
-	    s++;
-	    continue;
-	}
-	if (*s == ')')
-	{
-	    s++;
-	    if (--groupdepth < 0)
-		break;
-	    continue;
-	}
-	if (*s == '-')
-	    s++;
-	while (VIM_ISDIGIT(*s))
-	    s++;
-	if (*s == STL_USER_HL)
-	    continue;
-	if (*s == '.')
-	{
-	    s++;
-	    while (*s && VIM_ISDIGIT(*s))
-		s++;
-	}
-	if (*s == '(')
-	{
-	    groupdepth++;
-	    continue;
-	}
-	if (vim_strchr(STL_ALL, *s) == NULL)
-	{
-	    return illegal_char(errbuf, *s);
-	}
-	if (*s == '{')
-	{
-	    int reevaluate = (*++s == '%');
-
-	    if (reevaluate && *++s == '}')
-		// "}" is not allowed immediately after "%{%"
-		return illegal_char(errbuf, '}');
-	    while ((*s != '}' || (reevaluate && s[-1] != '%')) && *s)
-		s++;
-	    if (*s != '}')
-		return e_unclosed_expression_sequence;
-	}
-    }
-    if (groupdepth != 0)
-	return e_unbalanced_groups;
-    return NULL;
-}
-#endif
-
-/*
- * Check for a "normal" directory or file name in some options.  Disallow a
- * path separator (slash and/or backslash), wildcards and characters that are
- * often illegal in a file name. Be more permissive if "secure" is off.
- */
-    static int
-check_illegal_path_names(int opt_idx, char_u **varp)
-{
-    return (((get_option_flags(opt_idx) & P_NFNAME)
-		&& vim_strpbrk(*varp, (char_u *)(secure
-			? "/\\*?[|;&<>\r\n" : "/\\*?[<>\r\n")) != NULL)
-	    || ((get_option_flags(opt_idx) & P_NDNAME)
-		&& vim_strpbrk(*varp, (char_u *)"*?[|;&<>\r\n") != NULL));
-}
-
-/*
- * An option that accepts a list of flags is changed.
- * e.g. 'viewoptions', 'switchbuf', 'casemap', etc.
- */
-    static char *
-did_set_opt_flags(char_u *val, char **values, unsigned *flagp, int list)
-{
-    if (opt_strings_flags(val, values, flagp, list) == FAIL)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * An option that accepts a list of string values is changed.
- * e.g. 'nrformats', 'scrollopt', 'wildoptions', etc.
- */
-    static char *
-did_set_opt_strings(char_u *val, char **values, int list)
-{
-    return did_set_opt_flags(val, values, NULL, list);
-}
-
-/*
- * An option which is a list of flags is set.  Valid values are in 'flags'.
- */
-    static char *
-did_set_option_listflag(char_u *val, char_u *flags, char *errbuf)
-{
-    char_u	*s;
-
-    for (s = val; *s; ++s)
-	if (vim_strchr(flags, *s) == NULL)
-	    return illegal_char(errbuf, *s);
-
-    return NULL;
-}
-
-/*
- * The 'ambiwidth' option is changed.
- */
-    char *
-did_set_ambiwidth(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_ambw, p_ambw_values, FALSE) != OK)
-	return e_invalid_argument;
-
-    return check_chars_options();
-}
-
-/*
- * The 'background' option is changed.
- */
-    char *
-did_set_background(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_bg, p_bg_values, FALSE) == FAIL)
-	return e_invalid_argument;
-
-#ifdef FEAT_EVAL
-    int dark = (*p_bg == 'd');
-#endif
-
-    init_highlight(FALSE, FALSE);
-
-#ifdef FEAT_EVAL
-    if (dark != (*p_bg == 'd')
-	    && get_var_value((char_u *)"g:colors_name") != NULL)
-    {
-	// The color scheme must have set 'background' back to another
-	// value, that's not what we want here.  Disable the color
-	// scheme and set the colors again.
-	do_unlet((char_u *)"g:colors_name", TRUE);
-	free_string_option(p_bg);
-	p_bg = vim_strsave((char_u *)(dark ? "dark" : "light"));
-	check_string_option(&p_bg);
-	init_highlight(FALSE, FALSE);
-    }
-#endif
-#ifdef FEAT_TERMINAL
-    term_update_colors_all();
-#endif
-
-    return NULL;
-}
-
-/*
- * The 'backspace' option is changed.
- */
-    char *
-did_set_backspace(optset_T *args UNUSED)
-{
-    if (VIM_ISDIGIT(*p_bs))
-    {
-	if (*p_bs > '3' || p_bs[1] != NUL)
-	    return e_invalid_argument;
-    }
-    else if (check_opt_strings(p_bs, p_bs_values, TRUE) != OK)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * The 'backupcopy' option is changed.
- */
-    char *
-did_set_backupcopy(optset_T *args)
-{
-    char_u		*bkc = p_bkc;
-    unsigned int	*flags = &bkc_flags;
-    char		*errmsg = NULL;
-
-    if (args->os_flags & OPT_LOCAL)
-    {
-	bkc = curbuf->b_p_bkc;
-	flags = &curbuf->b_bkc_flags;
-    }
-
-    if ((args->os_flags & OPT_LOCAL) && *bkc == NUL)
-	// make the local value empty: use the global value
-	*flags = 0;
-    else
-    {
-	if (opt_strings_flags(bkc, p_bkc_values, flags, TRUE) != OK)
-	    errmsg = e_invalid_argument;
-	if ((((int)*flags & BKC_AUTO) != 0)
-		+ (((int)*flags & BKC_YES) != 0)
-		+ (((int)*flags & BKC_NO) != 0) != 1)
-	{
-	    // Must have exactly one of "auto", "yes"  and "no".
-	    (void)opt_strings_flags(args->os_oldval.string, p_bkc_values,
-								  flags, TRUE);
-	    errmsg = e_invalid_argument;
-	}
-    }
-
-    return errmsg;
-}
-
-/*
- * The 'backupext' or the 'patchmode' option is changed.
- */
-    char *
-did_set_backupext_or_patchmode(optset_T *args UNUSED)
-{
-    if (STRCMP(*p_bex == '.' ? p_bex + 1 : p_bex,
-		*p_pm == '.' ? p_pm + 1 : p_pm) == 0)
-	return e_backupext_and_patchmode_are_equal;
-
-    return NULL;
-}
-
-/*
- * The 'belloff' option is changed.
- */
-    char *
-did_set_belloff(optset_T *args UNUSED)
-{
-    return did_set_opt_flags(p_bo, p_bo_values, &bo_flags, TRUE);
-}
-
-#if defined(FEAT_LINEBREAK) || defined(PROTO)
-/*
- * The 'breakindentopt' option is changed.
- */
-    char *
-did_set_breakindentopt(optset_T *args UNUSED)
-{
-    char *errmsg = NULL;
-
-    if (briopt_check(curwin) == FAIL)
-	errmsg = e_invalid_argument;
-    // list setting requires a redraw
-    if (curwin->w_briopt_list)
-	redraw_all_later(UPD_NOT_VALID);
-
-    return errmsg;
-}
-#endif
-
-#if defined(FEAT_BROWSE) || defined(PROTO)
-/*
- * The 'browsedir' option is changed.
- */
-    char *
-did_set_browsedir(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_bsdir, p_bsdir_values, FALSE) != OK
-	    && !mch_isdir(p_bsdir))
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'bufhidden' option is changed.
- */
-    char *
-did_set_bufhidden(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(curbuf->b_p_bh, p_bufhidden_values, FALSE);
-}
-
-/*
- * The 'buftype' option is changed.
- */
-    char *
-did_set_buftype(optset_T *args UNUSED)
-{
-    if (check_opt_strings(curbuf->b_p_bt, p_buftype_values, FALSE) != OK)
-	return e_invalid_argument;
-
-    if (curwin->w_status_height)
-    {
-	curwin->w_redr_status = TRUE;
-	redraw_later(UPD_VALID);
-    }
-    curbuf->b_help = (curbuf->b_p_bt[0] == 'h');
-    redraw_titles();
-
-    return NULL;
-}
-
-/*
- * The 'casemap' option is changed.
- */
-    char *
-did_set_casemap(optset_T *args UNUSED)
-{
-    return did_set_opt_flags(p_cmp, p_cmp_values, &cmp_flags, TRUE);
-}
-
-/*
- * The global 'listchars' or 'fillchars' option is changed.
- */
-    static char *
-did_set_global_listfillchars(char_u *val, int opt_lcs, int opt_flags)
-{
-    char	*errmsg = NULL;
-    char_u	**local_ptr = opt_lcs ? &curwin->w_p_lcs : &curwin->w_p_fcs;
-
-    // only apply the global value to "curwin" when it does not have a
-    // local value
-    if (opt_lcs)
-	errmsg = set_listchars_option(curwin, val,
-		**local_ptr == NUL || !(opt_flags & OPT_GLOBAL));
-    else
-	errmsg = set_fillchars_option(curwin, val,
-		**local_ptr == NUL || !(opt_flags & OPT_GLOBAL));
-    if (errmsg != NULL)
-	return errmsg;
-
-    tabpage_T	*tp;
-    win_T	*wp;
-
-    // If the current window is set to use the global
-    // 'listchars'/'fillchars' value, clear the window-local value.
-    if (!(opt_flags & OPT_GLOBAL))
-	clear_string_option(local_ptr);
-    FOR_ALL_TAB_WINDOWS(tp, wp)
-    {
-	// If the current window has a local value need to apply it
-	// again, it was changed when setting the global value.
-	// If no error was returned above, we don't expect an error
-	// here, so ignore the return value.
-	if (opt_lcs)
-	{
-	    if (*wp->w_p_lcs == NUL)
-		(void)set_listchars_option(wp, wp->w_p_lcs, TRUE);
-	}
-	else
-	{
-	    if (*wp->w_p_fcs == NUL)
-		(void)set_fillchars_option(wp, wp->w_p_fcs, TRUE);
-	}
-    }
-
-    redraw_all_later(UPD_NOT_VALID);
-
-    return NULL;
-}
-
-/*
- * The 'fillchars' option or the 'listchars' option is changed.
- */
-    char *
-did_set_chars_option(optset_T *args)
-{
-    char_u **varp = (char_u **)args->os_varp;
-    char *errmsg = NULL;
-
-    if (   varp == &p_lcs		// global 'listchars'
-	|| varp == &p_fcs)		// global 'fillchars'
-	errmsg = did_set_global_listfillchars(*varp, varp == &p_lcs,
-							       args->os_flags);
-    else if (varp == &curwin->w_p_lcs)	// local 'listchars'
-	errmsg = set_listchars_option(curwin, *varp, TRUE);
-    else if (varp == &curwin->w_p_fcs)	// local 'fillchars'
-	errmsg = set_fillchars_option(curwin, *varp, TRUE);
-
-    return errmsg;
-}
-
-/*
- * The 'cinoptions' option is changed.
- */
-    char *
-did_set_cinoptions(optset_T *args UNUSED)
-{
-    // TODO: recognize errors
-    parse_cino(curbuf);
-
-    return NULL;
-}
-
-#if defined(FEAT_SYN_HL) || defined(PROTO)
-/*
- * The 'colorcolumn' option is changed.
- */
-    char *
-did_set_colorcolumn(optset_T *args UNUSED)
-{
-    return check_colorcolumn(curwin);
-}
-#endif
-
-/*
- * The 'comments' option is changed.
- */
-    char *
-did_set_comments(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u	*s;
-    char	*errmsg = NULL;
-
-    for (s = *varp; *s; )
-    {
-	while (*s && *s != ':')
-	{
-	    if (vim_strchr((char_u *)COM_ALL, *s) == NULL
-		    && !VIM_ISDIGIT(*s) && *s != '-')
-	    {
-		errmsg = illegal_char(args->os_errbuf, *s);
-		break;
-	    }
-	    ++s;
-	}
-	if (*s++ == NUL)
-	    errmsg = e_missing_colon;
-	else if (*s == ',' || *s == NUL)
-	    errmsg = e_zero_length_string;
-	if (errmsg != NULL)
-	    break;
-	while (*s && *s != ',')
-	{
-	    if (*s == '\\' && s[1] != NUL)
-		++s;
-	    ++s;
-	}
-	s = skip_to_option_part(s);
-    }
-
-    return errmsg;
-}
-
-#if defined(FEAT_FOLDING) || defined(PROTO)
-/*
- * The 'commentstring' option is changed.
- */
-    char *
-did_set_commentstring(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (**varp != NUL && strstr((char *)*varp, "%s") == NULL)
-	return e_commentstring_must_be_empty_or_contain_str;
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'complete' option is changed.
- */
-    char *
-did_set_complete(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u	*s;
-
-    // check if it is a valid value for 'complete' -- Acevedo
-    for (s = *varp; *s;)
-    {
-	while (*s == ',' || *s == ' ')
-	    s++;
-	if (!*s)
-	    break;
-	if (vim_strchr((char_u *)".wbuksid]tU", *s) == NULL)
-	    return illegal_char(args->os_errbuf, *s);
-	if (*++s != NUL && *s != ',' && *s != ' ')
-	{
-	    if (s[-1] == 'k' || s[-1] == 's')
-	    {
-		// skip optional filename after 'k' and 's'
-		while (*s && *s != ',' && *s != ' ')
-		{
-		    if (*s == '\\' && s[1] != NUL)
-			++s;
-		    ++s;
-		}
-	    }
-	    else
-	    {
-		if (args->os_errbuf != NULL)
-		{
-		    sprintf((char *)args->os_errbuf,
-			    _(e_illegal_character_after_chr), *--s);
-		    return args->os_errbuf;
-		}
-		return "";
-	    }
-	}
-    }
-
-    return NULL;
-}
-
-/*
- * The 'completeopt' option is changed.
- */
-    char *
-did_set_completeopt(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_cot, p_cot_values, TRUE) != OK)
-	return e_invalid_argument;
-
-    completeopt_was_set();
-    return NULL;
-}
-
-#if (defined(FEAT_PROP_POPUP) && defined(FEAT_QUICKFIX)) || defined(PROTO)
-/*
- * The 'completepopup' option is changed.
- */
-    char *
-did_set_completepopup(optset_T *args UNUSED)
-{
-    if (parse_completepopup(NULL) == FAIL)
-	return e_invalid_argument;
-
-    popup_close_info();
-    return NULL;
-}
-#endif
-
-#if defined(BACKSLASH_IN_FILENAME) || defined(PROTO)
-/*
- * The 'completeslash' option is changed.
- */
-    char *
-did_set_completeslash(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_csl, p_csl_values, FALSE) != OK
-	    || check_opt_strings(curbuf->b_p_csl, p_csl_values, FALSE) != OK)
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_CONCEAL) || defined(PROTO)
-/*
- * The 'concealcursor' option is changed.
- */
-    char *
-did_set_concealcursor(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    return did_set_option_listflag(*varp, (char_u *)COCU_ALL, args->os_errbuf);
-}
-#endif
-
-/*
- * The 'cpoptions' option is changed.
- */
-    char *
-did_set_cpoptions(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    return did_set_option_listflag(*varp, (char_u *)CPO_ALL, args->os_errbuf);
-}
-
-#if defined(FEAT_CRYPT) || defined(PROTO)
-/*
- * The 'cryptkey' option is changed.
- */
-    char *
-did_set_cryptkey(optset_T *args)
-{
-    // Make sure the ":set" command doesn't show the new value in the
-    // history.
-    remove_key_from_history();
-
-    if (STRCMP(curbuf->b_p_key, args->os_oldval.string) != 0)
-    {
-	// Need to update the swapfile.
-	ml_set_crypt_key(curbuf, args->os_oldval.string,
-		*curbuf->b_p_cm == NUL ? p_cm : curbuf->b_p_cm);
-	changed_internal();
-    }
-
-    return NULL;
-}
-
-/*
- * The 'cryptmethod' option is changed.
- */
-    char *
-did_set_cryptmethod(optset_T *args)
-{
-    char_u  *p;
-    char_u  *s;
-
-    if (args->os_flags & OPT_LOCAL)
-	p = curbuf->b_p_cm;
-    else
-	p = p_cm;
-    if (check_opt_strings(p, p_cm_values, TRUE) != OK)
-	return e_invalid_argument;
-    else if (crypt_self_test() == FAIL)
-	return e_invalid_argument;
-
-    // When setting the global value to empty, make it "zip".
-    if (*p_cm == NUL)
-    {
-	free_string_option(p_cm);
-	p_cm = vim_strsave((char_u *)"zip");
-    }
-    // When using ":set cm=name" the local value is going to be empty.
-    // Do that here, otherwise the crypt functions will still use the
-    // local value.
-    if ((args->os_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0)
-    {
-	free_string_option(curbuf->b_p_cm);
-	curbuf->b_p_cm = empty_option;
-    }
-
-    // Need to update the swapfile when the effective method changed.
-    // Set "s" to the effective old value, "p" to the effective new
-    // method and compare.
-    if ((args->os_flags & OPT_LOCAL) && *args->os_oldval.string == NUL)
-	s = p_cm;  // was previously using the global value
-    else
-	s = args->os_oldval.string;
-    if (*curbuf->b_p_cm == NUL)
-	p = p_cm;  // is now using the global value
-    else
-	p = curbuf->b_p_cm;
-    if (STRCMP(s, p) != 0)
-	ml_set_crypt_key(curbuf, curbuf->b_p_key, s);
-
-    // If the global value changes need to update the swapfile for all
-    // buffers using that value.
-    if ((args->os_flags & OPT_GLOBAL)
-	    && STRCMP(p_cm, args->os_oldval.string) != 0)
-    {
-	buf_T	*buf;
-
-	FOR_ALL_BUFFERS(buf)
-	    if (buf != curbuf && *buf->b_p_cm == NUL)
-		ml_set_crypt_key(buf, buf->b_p_key, args->os_oldval.string);
-    }
-    return NULL;
-}
-#endif
-
-#if (defined(FEAT_CSCOPE) && defined(FEAT_QUICKFIX)) || defined(PROTO)
-/*
- * The 'cscopequickfix' option is changed.
- */
-    char *
-did_set_cscopequickfix(optset_T *args UNUSED)
-{
-    char_u	*p;
-
-    if (p_csqf == NULL)
-	return NULL;
-
-    p = p_csqf;
-    while (*p != NUL)
-    {
-	if (vim_strchr((char_u *)CSQF_CMDS, *p) == NULL
-		|| p[1] == NUL
-		|| vim_strchr((char_u *)CSQF_FLAGS, p[1]) == NULL
-		|| (p[2] != NUL && p[2] != ','))
-	    return e_invalid_argument;
-	else if (p[2] == NUL)
-	    break;
-	else
-	    p += 3;
-    }
-
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_SYN_HL) || defined(PROTO)
-/*
- * The 'cursorlineopt' option is changed.
- */
-    char *
-did_set_cursorlineopt(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (**varp == NUL || fill_culopt_flags(*varp, curwin) != OK)
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'debug' option is changed.
- */
-    char *
-did_set_debug(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_debug, p_debug_values, TRUE);
-}
-
-#if defined(FEAT_DIFF) || defined(PROTO)
-/*
- * The 'diffopt' option is changed.
- */
-    char *
-did_set_diffopt(optset_T *args UNUSED)
-{
-    if (diffopt_changed() == FAIL)
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'display' option is changed.
- */
-    char *
-did_set_display(optset_T *args UNUSED)
-{
-    if (opt_strings_flags(p_dy, p_dy_values, &dy_flags, TRUE) != OK)
-	return e_invalid_argument;
-
-    (void)init_chartab();
-    return NULL;
-}
-
-/*
- * The 'eadirection' option is changed.
- */
-    char *
-did_set_eadirection(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_ead, p_ead_values, FALSE);
-}
-
-/*
- * One of the 'encoding', 'fileencoding', 'termencoding' or 'makeencoding'
- * options is changed.
- */
-    char *
-did_set_encoding(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u	**gvarp;
-    char	*errmsg = NULL;
-    char_u	*p;
-
-    // Get the global option to compare with, otherwise we would have to check
-    // two values for all local options.
-    gvarp = (char_u **)get_option_varp_scope(args->os_idx, OPT_GLOBAL);
-
-    if (gvarp == &p_fenc)
-    {
-	if (!curbuf->b_p_ma && args->os_flags != OPT_GLOBAL)
-	    errmsg = e_cannot_make_changes_modifiable_is_off;
-	else if (vim_strchr(*varp, ',') != NULL)
-	    // No comma allowed in 'fileencoding'; catches confusing it
-	    // with 'fileencodings'.
-	    errmsg = e_invalid_argument;
-	else
-	{
-	    // May show a "+" in the title now.
-	    redraw_titles();
-	    // Add 'fileencoding' to the swap file.
-	    ml_setflags(curbuf);
-	}
-    }
-    if (errmsg == NULL)
-    {
-	// canonize the value, so that STRCMP() can be used on it
-	p = enc_canonize(*varp);
-	if (p != NULL)
-	{
-	    vim_free(*varp);
-	    *varp = p;
-	}
-	if (varp == &p_enc)
-	{
-	    errmsg = mb_init();
-	    redraw_titles();
-	}
-    }
-
-#if defined(FEAT_GUI_GTK)
-    if (errmsg == NULL && varp == &p_tenc && gui.in_use)
-    {
-	// GTK uses only a single encoding, and that is UTF-8.
-	if (STRCMP(p_tenc, "utf-8") != 0)
-	    errmsg = e_cannot_be_changed_in_gtk_GUI;
-    }
-#endif
-
-    if (errmsg == NULL)
-    {
-#ifdef FEAT_KEYMAP
-	// When 'keymap' is used and 'encoding' changes, reload the keymap
-	// (with another encoding).
-	if (varp == &p_enc && *curbuf->b_p_keymap != NUL)
-	    (void)keymap_init();
-#endif
-
-	// When 'termencoding' is not empty and 'encoding' changes or when
-	// 'termencoding' changes, need to setup for keyboard input and
-	// display output conversion.
-	if (((varp == &p_enc && *p_tenc != NUL) || varp == &p_tenc))
-	{
-	    if (convert_setup(&input_conv, p_tenc, p_enc) == FAIL
-		    || convert_setup(&output_conv, p_enc, p_tenc) == FAIL)
-	    {
-		semsg(_(e_cannot_convert_between_str_and_str),
-			p_tenc, p_enc);
-		errmsg = e_invalid_argument;
-	    }
-	}
-
-#if defined(MSWIN)
-	// $HOME, $VIM and $VIMRUNTIME may have characters in active code page.
-	if (varp == &p_enc)
-	{
-	    init_homedir();
-	    init_vimdir();
-	}
-#endif
-    }
-
-    return errmsg;
-}
-
-/*
- * The 'eventignore' option is changed.
- */
-    char *
-did_set_eventignore(optset_T *args UNUSED)
-{
-    if (check_ei() == FAIL)
-	return e_invalid_argument;
-    return NULL;
-}
-
-/*
- * The 'fileformat' option is changed.
- */
-    char *
-did_set_fileformat(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (!curbuf->b_p_ma && !(args->os_flags & OPT_GLOBAL))
-	return e_cannot_make_changes_modifiable_is_off;
-    else if (check_opt_strings(*varp, p_ff_values, FALSE) != OK)
-	return e_invalid_argument;
-
-    // may also change 'textmode'
-    if (get_fileformat(curbuf) == EOL_DOS)
-	curbuf->b_p_tx = TRUE;
-    else
-	curbuf->b_p_tx = FALSE;
-    redraw_titles();
-    // update flag in swap file
-    ml_setflags(curbuf);
-    // Redraw needed when switching to/from "mac": a CR in the text
-    // will be displayed differently.
-    if (get_fileformat(curbuf) == EOL_MAC || *args->os_oldval.string == 'm')
-	redraw_curbuf_later(UPD_NOT_VALID);
-
-    return NULL;
-}
-
-/*
- * The 'fileformats' option is changed.
- */
-    char *
-did_set_fileformats(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_ffs, p_ff_values, TRUE) != OK)
-	return e_invalid_argument;
-
-    // also change 'textauto'
-    if (*p_ffs == NUL)
-	p_ta = FALSE;
-    else
-	p_ta = TRUE;
-
-    return NULL;
-}
-
-/*
- * The 'filetype' or the 'syntax' option is changed.
- */
-    char *
-did_set_filetype_or_syntax(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (!valid_filetype(*varp))
-	return e_invalid_argument;
-
-    args->os_value_changed = STRCMP(args->os_oldval.string, *varp) != 0;
-
-    // Since we check the value, there is no need to set P_INSECURE,
-    // even when the value comes from a modeline.
-    args->os_value_checked = TRUE;
-
-    return NULL;
-}
-
-#if defined(FEAT_FOLDING) || defined(PROTO)
-/*
- * The 'foldclose' option is changed.
- */
-    char *
-did_set_foldclose(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_fcl, p_fcl_values, TRUE);
-}
-#endif
-
-#if (defined(FEAT_EVAL) && defined(FEAT_FOLDING)) || defined(PROTO)
-/*
- * The 'foldexpr' option is changed.
- */
-    char *
-did_set_foldexpr(optset_T *args)
-{
-    (void)did_set_optexpr(args);
-    if (foldmethodIsExpr(curwin))
-	foldUpdateAll(curwin);
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_FOLDING) || defined(PROTO)
-/*
- * The 'foldignore' option is changed.
- */
-    char *
-did_set_foldignore(optset_T *args UNUSED)
-{
-    if (foldmethodIsIndent(curwin))
-	foldUpdateAll(curwin);
-    return NULL;
-}
-
-/*
- * The 'foldmarker' option is changed.
- */
-    char *
-did_set_foldmarker(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u	*p;
-
-    p = vim_strchr(*varp, ',');
-    if (p == NULL)
-	return e_comma_required;
-    else if (p == *varp || p[1] == NUL)
-	return e_invalid_argument;
-    else if (foldmethodIsMarker(curwin))
-	foldUpdateAll(curwin);
-
-    return NULL;
-}
-
-/*
- * The 'foldmethod' option is changed.
- */
-    char *
-did_set_foldmethod(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (check_opt_strings(*varp, p_fdm_values, FALSE) != OK
-	    || *curwin->w_p_fdm == NUL)
-	return e_invalid_argument;
-
-    foldUpdateAll(curwin);
-    if (foldmethodIsDiff(curwin))
-	newFoldLevel();
-    return NULL;
-}
-
-/*
- * The 'foldopen' option is changed.
- */
-    char *
-did_set_foldopen(optset_T *args UNUSED)
-{
-    return did_set_opt_flags(p_fdo, p_fdo_values, &fdo_flags, TRUE);
-}
-#endif
-
-/*
- * The 'formatoptions' option is changed.
- */
-    char *
-did_set_formatoptions(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    return did_set_option_listflag(*varp, (char_u *)FO_ALL, args->os_errbuf);
-}
-
-#if defined(CURSOR_SHAPE) || defined(PROTO)
-/*
- * The 'guicursor' option is changed.
- */
-    char *
-did_set_guicursor(optset_T *args UNUSED)
-{
-    return parse_shape_opt(SHAPE_CURSOR);
-}
-#endif
-
-#if defined(FEAT_GUI) || defined(PROTO)
-/*
- * The 'guifont' option is changed.
- */
-    char *
-did_set_guifont(optset_T *args UNUSED)
-{
-    char_u	*p;
-    char	*errmsg = NULL;
-
-    if (gui.in_use)
-    {
-	p = p_guifont;
-# if defined(FEAT_GUI_GTK)
-	// Put up a font dialog and let the user select a new value.
-	// If this is cancelled go back to the old value but don't
-	// give an error message.
-	if (STRCMP(p, "*") == 0)
-	{
-	    p = gui_mch_font_dialog(args->os_oldval.string);
-	    free_string_option(p_guifont);
-	    p_guifont = (p != NULL) ? p : vim_strsave(args->os_oldval.string);
-	}
-# endif
-	if (p != NULL && gui_init_font(p_guifont, FALSE) != OK)
-	{
-# if defined(FEAT_GUI_MSWIN) || defined(FEAT_GUI_PHOTON)
-	    if (STRCMP(p_guifont, "*") == 0)
-	    {
-		// Dialog was cancelled: Keep the old value without giving
-		// an error message.
-		free_string_option(p_guifont);
-		p_guifont = vim_strsave(args->os_oldval.string);
-	    }
-	    else
-# endif
-		errmsg = e_invalid_fonts;
-	}
-    }
-
-    return errmsg;
-}
-
-# if defined(FEAT_XFONTSET) || defined(PROTO)
-/*
- * The 'guifontset' option is changed.
- */
-    char *
-did_set_guifontset(optset_T *args UNUSED)
-{
-    char *errmsg = NULL;
-
-    if (STRCMP(p_guifontset, "*") == 0)
-	errmsg = e_cant_select_fontset;
-    else if (gui.in_use && gui_init_font(p_guifontset, TRUE) != OK)
-	errmsg = e_invalid_fontset;
-
-    return errmsg;
-}
-# endif
-
-/*
- * The 'guifontwide' option is changed.
- */
-    char *
-did_set_guifontwide(optset_T *args UNUSED)
-{
-    char *errmsg = NULL;
-
-    if (STRCMP(p_guifontwide, "*") == 0)
-	errmsg = e_cant_select_wide_font;
-    else if (gui_get_wide_font() == FAIL)
-	errmsg = e_invalid_wide_font;
-
-    return errmsg;
-}
-#endif
-
-#if defined(FEAT_GUI_GTK) || defined(PROTO)
-/*
- * The 'guiligatures' option is changed.
- */
-    char *
-did_set_guiligatures(optset_T *args UNUSED)
-{
-    gui_set_ligatures();
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_GUI) || defined(PROTO)
-/*
- * The 'guioptions' option is changed.
- */
-    char *
-did_set_guioptions(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char *errmsg;
-
-    errmsg = did_set_option_listflag(*varp, (char_u *)GO_ALL, args->os_errbuf);
-    if (errmsg != NULL)
-	return errmsg;
-
-    gui_init_which_components(args->os_oldval.string);
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_GUI_TABLINE) || defined(PROTO)
-/*
- * The 'guitablabel' option is changed.
- */
-    char *
-did_set_guitablabel(optset_T *args UNUSED)
-{
-    redraw_tabline = TRUE;
-    return NULL;
-}
-#endif
-
-/*
- * The 'helpfile' option is changed.
- */
-    char *
-did_set_helpfile(optset_T *args UNUSED)
-{
-    // May compute new values for $VIM and $VIMRUNTIME
-    if (didset_vim)
-	vim_unsetenv_ext((char_u *)"VIM");
-    if (didset_vimruntime)
-	vim_unsetenv_ext((char_u *)"VIMRUNTIME");
-    return NULL;
-}
-
-#if defined(FEAT_MULTI_LANG) || defined(PROTO)
-/*
- * The 'helplang' option is changed.
- */
-    char *
-did_set_helplang(optset_T *args UNUSED)
-{
-    char *errmsg = NULL;
-
-    // Check for "", "ab", "ab,cd", etc.
-    for (char_u *s = p_hlg; *s != NUL; s += 3)
-    {
-	if (s[1] == NUL || ((s[2] != ',' || s[3] == NUL) && s[2] != NUL))
-	{
-	    errmsg = e_invalid_argument;
-	    break;
-	}
-	if (s[2] == NUL)
-	    break;
-    }
-
-    return errmsg;
-}
-#endif
-
-/*
- * The 'highlight' option is changed.
- */
-    char *
-did_set_highlight(optset_T *args UNUSED)
-{
-    if (highlight_changed() == FAIL)
-	return e_invalid_argument;	// invalid flags
-
-    return NULL;
-}
-
-/*
- * The 'titlestring' or the 'iconstring' option is changed.
- */
-    static char *
-parse_titleiconstring(optset_T *args UNUSED, int flagval UNUSED)
-{
-#ifdef FEAT_STL_OPT
-    char_u	**varp = (char_u **)args->os_varp;
-
-    // NULL => statusline syntax
-    if (vim_strchr(*varp, '%') && check_stl_option(*varp) == NULL)
-	stl_syntax |= flagval;
-    else
-	stl_syntax &= ~flagval;
-#endif
-    did_set_title();
-
-    return NULL;
-}
-
-/*
- * The 'iconstring' option is changed.
- */
-    char *
-did_set_iconstring(optset_T *args)
-{
-    int flagval = 0;
-
-#ifdef FEAT_STL_OPT
-    flagval = STL_IN_ICON;
-#endif
-
-    return parse_titleiconstring(args, flagval);
-}
-
-#if (defined(FEAT_XIM) && defined(FEAT_GUI_GTK)) || defined(PROTO)
-/*
- * The 'imactivatekey' option is changed.
- */
-    char *
-did_set_imactivatekey(optset_T *args UNUSED)
-{
-    if (!im_xim_isvalid_imactivate())
-	return e_invalid_argument;
-    return NULL;
-}
-#endif
-
-/*
- * The 'isident' or the 'iskeyword' or the 'isprint' or the 'isfname' option is
- * changed.
- */
-    char *
-did_set_isopt(optset_T *args)
-{
-    // 'isident', 'iskeyword', 'isprint or 'isfname' option: refill g_chartab[]
-    // If the new option is invalid, use old value.
-    // 'lisp' option: refill g_chartab[] for '-' char.
-    if (init_chartab() == FAIL)
-    {
-	args->os_restore_chartab = TRUE;// need to restore the chartab.
-	return e_invalid_argument;	// error in value
-    }
-
-    return NULL;
-}
-
-#if defined(FEAT_KEYMAP) || defined(PROTO)
-/*
- * The 'keymap' option is changed.
- */
-    char *
-did_set_keymap(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char *errmsg = NULL;
-
-    if (!valid_filetype(*varp))
-	errmsg = e_invalid_argument;
-    else
-    {
-	int	    secure_save = secure;
-
-	// Reset the secure flag, since the value of 'keymap' has
-	// been checked to be safe.
-	secure = 0;
-
-	// load or unload key mapping tables
-	errmsg = keymap_init();
-
-	secure = secure_save;
-
-	// Since we check the value, there is no need to set P_INSECURE,
-	// even when the value comes from a modeline.
-	args->os_value_checked = TRUE;
-    }
-
-    if (errmsg == NULL)
-    {
-	if (*curbuf->b_p_keymap != NUL)
-	{
-	    // Installed a new keymap, switch on using it.
-	    curbuf->b_p_iminsert = B_IMODE_LMAP;
-	    if (curbuf->b_p_imsearch != B_IMODE_USE_INSERT)
-		curbuf->b_p_imsearch = B_IMODE_LMAP;
-	}
-	else
-	{
-	    // Cleared the keymap, may reset 'iminsert' and 'imsearch'.
-	    if (curbuf->b_p_iminsert == B_IMODE_LMAP)
-		curbuf->b_p_iminsert = B_IMODE_NONE;
-	    if (curbuf->b_p_imsearch == B_IMODE_LMAP)
-		curbuf->b_p_imsearch = B_IMODE_USE_INSERT;
-	}
-	if ((args->os_flags & OPT_LOCAL) == 0)
-	{
-	    set_iminsert_global();
-	    set_imsearch_global();
-	}
-	status_redraw_curbuf();
-    }
-
-    return errmsg;
-}
-#endif
-
-/*
- * The 'keymodel' option is changed.
- */
-    char *
-did_set_keymodel(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_km, p_km_values, TRUE) != OK)
-	return e_invalid_argument;
-
-    km_stopsel = (vim_strchr(p_km, 'o') != NULL);
-    km_startsel = (vim_strchr(p_km, 'a') != NULL);
-    return NULL;
-}
-
-/*
- * The 'keyprotocol' option is changed.
- */
-    char *
-did_set_keyprotocol(optset_T *args UNUSED)
-{
-    if (match_keyprotocol(NULL) == KEYPROTOCOL_FAIL)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * The 'lispoptions' option is changed.
- */
-    char *
-did_set_lispoptions(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (**varp != NUL
-	    && STRCMP(*varp, "expr:0") != 0
-	    && STRCMP(*varp, "expr:1") != 0)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * The 'matchpairs' option is changed.
- */
-    char *
-did_set_matchpairs(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u	*p;
-
-    if (has_mbyte)
-    {
-	for (p = *varp; *p != NUL; ++p)
-	{
-	    int x2 = -1;
-	    int x3 = -1;
-
-	    p += mb_ptr2len(p);
-	    if (*p != NUL)
-		x2 = *p++;
-	    if (*p != NUL)
-	    {
-		x3 = mb_ptr2char(p);
-		p += mb_ptr2len(p);
-	    }
-	    if (x2 != ':' || x3 == -1 || (*p != NUL && *p != ','))
-		return e_invalid_argument;
-	    if (*p == NUL)
-		break;
-	}
-    }
-    else
-    {
-	// Check for "x:y,x:y"
-	for (p = *varp; *p != NUL; p += 4)
-	{
-	    if (p[1] != ':' || p[2] == NUL || (p[3] != NUL && p[3] != ','))
-		return e_invalid_argument;
-	    if (p[3] == NUL)
-		break;
-	}
-    }
-
-    return NULL;
-}
-
-#if defined(FEAT_SPELL) || defined(PROTO)
-/*
- * The 'mkspellmem' option is changed.
- */
-    char *
-did_set_mkspellmem(optset_T *args UNUSED)
-{
-    if (spell_check_msm() != OK)
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'mouse' option is changed.
- */
-    char *
-did_set_mouse(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    return did_set_option_listflag(*varp, (char_u *)MOUSE_ALL,
-							args->os_errbuf);
-}
-
-/*
- * The 'mousemodel' option is changed.
- */
-    char *
-did_set_mousemodel(optset_T *args UNUSED)
-{
-    if (check_opt_strings(p_mousem, p_mousem_values, FALSE) != OK)
-	return e_invalid_argument;
-#if defined(FEAT_GUI_MOTIF) && defined(FEAT_MENU) && (XmVersion <= 1002)
-    else if (*p_mousem != *oldval)
-	// Changed from "extend" to "popup" or "popup_setpos" or vv: need
-	// to create or delete the popup menus.
-	gui_motif_update_mousemodel(root_menu);
-#endif
-
-    return NULL;
-}
-
-#if defined(FEAT_MOUSESHAPE) || defined(PROTO)
-    char *
-did_set_mouseshape(optset_T *args UNUSED)
-{
-    char *errmsg = NULL;
-
-    errmsg = parse_shape_opt(SHAPE_MOUSE);
-    update_mouseshape(-1);
-
-    return errmsg;
-}
-#endif
-
-/*
- * The 'nrformats' option is changed.
- */
-    char *
-did_set_nrformats(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    return did_set_opt_strings(*varp, p_nf_values, TRUE);
-}
-
-#if defined(FEAT_EVAL) || defined(PROTO)
-/*
- * One of the '*expr' options is changed: 'balloonexpr', 'diffexpr',
- * 'foldexpr', 'foldtext', 'formatexpr', 'includeexpr', 'indentexpr',
- * 'patchexpr', 'printexpr' and 'charconvert'.
- *
- */
-    char *
-did_set_optexpr(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    // If the option value starts with <SID> or s:, then replace that with
-    // the script identifier.
-    char_u *name = get_scriptlocal_funcname(*varp);
-    if (name != NULL)
-    {
-	free_string_option(*varp);
-	*varp = name;
-    }
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'pastetoggle' option is changed.
- */
-    char *
-did_set_pastetoggle(optset_T *args UNUSED)
-{
-    char_u	*p;
-
-    // translate key codes like in a mapping
-    if (*p_pt)
-    {
-	(void)replace_termcodes(p_pt, &p,
-		REPTERM_FROM_PART | REPTERM_DO_LT, NULL);
-	if (p != NULL)
-	{
-	    free_string_option(p_pt);
-	    p_pt = p;
-	}
-    }
-
-    return NULL;
-}
-
-#if defined(FEAT_PROP_POPUP) || defined(PROTO)
-/*
- * The 'previewpopup' option is changed.
- */
-    char *
-did_set_previewpopup(optset_T *args UNUSED)
-{
-    if (parse_previewpopup(NULL) == FAIL)
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_POSTSCRIPT) || defined(PROTO)
-/*
- * The 'printencoding' option is changed.
- */
-    char *
-did_set_printencoding(optset_T *args UNUSED)
-{
-    char_u	*s, *p;
-
-    // Canonize 'printencoding' if VIM standard one
-    p = enc_canonize(p_penc);
-    if (p != NULL)
-    {
-	vim_free(p_penc);
-	p_penc = p;
-    }
-    else
-    {
-	// Ensure lower case and '-' for '_'
-	for (s = p_penc; *s != NUL; s++)
-	{
-	    if (*s == '_')
-		*s = '-';
-	    else
-		*s = TOLOWER_ASC(*s);
-	}
-    }
-
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_STL_OPT) || defined(PROTO)
-/*
- * The 'statusline' or the 'tabline' or the 'rulerformat' option is changed.
- * "rulerformat" is TRUE if the 'rulerformat' option is changed.
- */
-    static char *
-parse_statustabline_rulerformat(optset_T *args, int rulerformat)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u	*s;
-    char	*errmsg = NULL;
-    int		wid;
-
-    if (rulerformat)	// reset ru_wid first
-	ru_wid = 0;
-    s = *varp;
-    if (rulerformat && *s == '%')
-    {
-	// set ru_wid if 'ruf' starts with "%99("
-	if (*++s == '-')	// ignore a '-'
-	    s++;
-	wid = getdigits(&s);
-	if (wid && *s == '(' && (errmsg = check_stl_option(p_ruf)) == NULL)
-	    ru_wid = wid;
-	else
-	    errmsg = check_stl_option(p_ruf);
-    }
-    // check 'statusline' or 'tabline' only if it doesn't start with "%!"
-    else if (rulerformat || s[0] != '%' || s[1] != '!')
-	errmsg = check_stl_option(s);
-    if (rulerformat && errmsg == NULL)
-	comp_col();
-
-    return errmsg;
-}
-#endif
-
-#if defined(FEAT_RENDER_OPTIONS) || defined(PROTO)
-/*
- * The 'renderoptions' option is changed.
- */
-    char *
-did_set_renderoptions(optset_T *args UNUSED)
-{
-    if (!gui_mch_set_rendering_options(p_rop))
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_RIGHTLEFT) || defined(PROTO)
-/*
- * The 'rightleftcmd' option is changed.
- */
-    char *
-did_set_rightleftcmd(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    // Currently only "search" is a supported value.
-    if (**varp != NUL && STRCMP(*varp, "search") != 0)
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_STL_OPT) || defined(PROTO)
-/*
- * The 'rulerformat' option is changed.
- */
-    char *
-did_set_rulerformat(optset_T *args)
-{
-    return parse_statustabline_rulerformat(args, TRUE);
-}
-#endif
-
-/*
- * The 'scrollopt' option is changed.
- */
-    char *
-did_set_scrollopt(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_sbo, p_scbopt_values, TRUE);
-}
-
-/*
- * The 'selection' option is changed.
- */
-    char *
-did_set_selection(optset_T *args UNUSED)
-{
-    if (*p_sel == NUL || check_opt_strings(p_sel, p_sel_values, FALSE) != OK)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * The 'selectmode' option is changed.
- */
-    char *
-did_set_selectmode(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_slm, p_slm_values, TRUE);
-}
-
-#if defined(FEAT_SESSION) || defined(PROTO)
-/*
- * The 'sessionoptions' option is changed.
- */
-    char *
-did_set_sessionoptions(optset_T *args)
-{
-    if (opt_strings_flags(p_ssop, p_ssop_values, &ssop_flags, TRUE) != OK)
-	return e_invalid_argument;
-    if ((ssop_flags & SSOP_CURDIR) && (ssop_flags & SSOP_SESDIR))
-    {
-	// Don't allow both "sesdir" and "curdir".
-	(void)opt_strings_flags(args->os_oldval.string, p_ssop_values,
-							&ssop_flags, TRUE);
-	return e_invalid_argument;
-    }
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'shortmess' option is changed.
- */
-    char *
-did_set_shortmess(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    return did_set_option_listflag(*varp, (char_u *)SHM_ALL, args->os_errbuf);
-}
-
-#if defined(FEAT_LINEBREAK) || defined(PROTO)
-/*
- * The 'showbreak' option is changed.
- */
-    char *
-did_set_showbreak(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u	*s;
-
-    for (s = *varp; *s; )
-    {
-	if (ptr2cells(s) != 1)
-	    return e_showbreak_contains_unprintable_or_wide_character;
-	MB_PTR_ADV(s);
-    }
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'showcmdloc' option is changed.
- */
-    char *
-did_set_showcmdloc(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_sloc, p_sloc_values, FALSE);
-}
-
-#if defined(FEAT_SIGNS) || defined(PROTO)
-/*
- * The 'signcolumn' option is changed.
- */
-    char *
-did_set_signcolumn(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (check_opt_strings(*varp, p_scl_values, FALSE) != OK)
-	return e_invalid_argument;
-    // When changing the 'signcolumn' to or from 'number', recompute the
-    // width of the number column if 'number' or 'relativenumber' is set.
-    if (((*args->os_oldval.string == 'n' && args->os_oldval.string[1] == 'u')
-		|| (*curwin->w_p_scl == 'n' && *(curwin->w_p_scl + 1) =='u'))
-	    && (curwin->w_p_nu || curwin->w_p_rnu))
-	curwin->w_nrwidth_line_count = 0;
-
-    return NULL;
-}
-#endif
-
-#if defined(FEAT_SPELL) || defined(PROTO)
-/*
- * The 'spellcapcheck' option is changed.
- */
-    char *
-did_set_spellcapcheck(optset_T *args UNUSED)
-{
-    // compile the regexp program.
-    return compile_cap_prog(curwin->w_s);
-}
-
-/*
- * The 'spellfile' option is changed.
- */
-    char *
-did_set_spellfile(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (!valid_spellfile(*varp))
-	return e_invalid_argument;
-
-    // If there is a window for this buffer in which 'spell' is set load the
-    // wordlists.
-    return did_set_spell_option(TRUE);
-}
-
-/*
- * The 'spell' option is changed.
- */
-    char *
-did_set_spelllang(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (!valid_spelllang(*varp))
-	return e_invalid_argument;
-
-    // If there is a window for this buffer in which 'spell' is set load the
-    // wordlists.
-    return did_set_spell_option(FALSE);
-}
-
-/*
- * The 'spelloptions' option is changed.
- */
-    char *
-did_set_spelloptions(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (**varp != NUL && STRCMP(*varp, "camel") != 0)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * The 'spellsuggest' option is changed.
- */
-    char *
-did_set_spellsuggest(optset_T *args UNUSED)
-{
-    if (spell_check_sps() != OK)
-	return e_invalid_argument;
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'splitkeep' option is changed.
- */
-    char *
-did_set_splitkeep(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_spk, p_spk_values, FALSE);
-}
-
-#if defined(FEAT_STL_OPT) || defined(PROTO)
-/*
- * The 'statusline' option is changed.
- */
-    char *
-did_set_statusline(optset_T *args)
-{
-    return parse_statustabline_rulerformat(args, FALSE);
-}
-#endif
-
-/*
- * The 'swapsync' option is changed.
- */
-    char *
-did_set_swapsync(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_sws, p_sws_values, FALSE);
-}
-
-/*
- * The 'switchbuf' option is changed.
- */
-    char *
-did_set_switchbuf(optset_T *args UNUSED)
-{
-    return did_set_opt_flags(p_swb, p_swb_values, &swb_flags, TRUE);
-}
-
-#if defined(FEAT_STL_OPT) || defined(PROTO)
-/*
- * The 'tabline' option is changed.
- */
-    char *
-did_set_tabline(optset_T *args)
-{
-    return parse_statustabline_rulerformat(args, FALSE);
-}
-#endif
-
-/*
- * The 'tagcase' option is changed.
- */
-    char *
-did_set_tagcase(optset_T *args)
-{
-    unsigned int	*flags;
-    char_u		*p;
-
-    if (args->os_flags & OPT_LOCAL)
-    {
-	p = curbuf->b_p_tc;
-	flags = &curbuf->b_tc_flags;
-    }
-    else
-    {
-	p = p_tc;
-	flags = &tc_flags;
-    }
-
-    if ((args->os_flags & OPT_LOCAL) && *p == NUL)
-	// make the local value empty: use the global value
-	*flags = 0;
-    else if (*p == NUL
-	    || opt_strings_flags(p, p_tc_values, flags, FALSE) != OK)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * The 'term' option is changed.
- */
-    char *
-did_set_term(optset_T *args UNUSED)
-{
-    if (T_NAME[0] == NUL)
-	return e_cannot_set_term_to_empty_string;
-#ifdef FEAT_GUI
-    if (gui.in_use)
-	return e_cannot_change_term_in_GUI;
-    if (term_is_gui(T_NAME))
-	return e_use_gui_to_start_GUI;
-#endif
-    if (set_termname(T_NAME) == FAIL)
-	return e_not_found_in_termcap;
-
-    // Screen colors may have changed.
-    redraw_later_clear();
-
-    return NULL;
-}
-
-/*
- * Some terminal option (t_xxx) is changed
- */
-    char *
-did_set_term_option(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    if (!full_screen)
-	return NULL;
-
-    // ":set t_Co=0" and ":set t_Co=1" do ":set t_Co="
-    if (varp == &T_CCO)
-    {
-	int colors = atoi((char *)T_CCO);
-
-	// Only reinitialize colors if t_Co value has really changed to
-	// avoid expensive reload of colorscheme if t_Co is set to the
-	// same value multiple times.
-	if (colors != t_colors)
-	{
-	    t_colors = colors;
-	    if (t_colors <= 1)
-	    {
-		vim_free(T_CCO);
-		T_CCO = empty_option;
-	    }
-#if defined(FEAT_VTP) && defined(FEAT_TERMGUICOLORS)
-	    if (is_term_win32())
-	    {
-		swap_tcap();
-		args->os_did_swaptcap = TRUE;
-	    }
-#endif
-	    // We now have a different color setup, initialize it again.
-	    init_highlight(TRUE, FALSE);
-	}
-    }
-    ttest(FALSE);
-    if (varp == &T_ME)
-    {
-	out_str(T_ME);
-	redraw_later(UPD_CLEAR);
-#if defined(MSWIN) && (!defined(FEAT_GUI_MSWIN) || defined(VIMDLL))
-	// Since t_me has been set, this probably means that the user
-	// wants to use this as default colors.  Need to reset default
-	// background/foreground colors.
-# ifdef VIMDLL
-	if (!gui.in_use && !gui.starting)
-# endif
-	    mch_set_normal_colors();
-#endif
-    }
-    if (varp == &T_BE && termcap_active)
-    {
-	MAY_WANT_TO_LOG_THIS;
-
-	if (*T_BE == NUL)
-	    // When clearing t_BE we assume the user no longer wants
-	    // bracketed paste, thus disable it by writing t_BD.
-	    out_str(T_BD);
-	else
-	    out_str(T_BE);
-    }
-
-    return NULL;
-}
-
-#if defined(FEAT_TERMINAL) || defined(PROTO)
-/*
- * The 'termwinkey' option is changed.
- */
-    char *
-did_set_termwinkey(optset_T *args UNUSED)
-{
-    if (*curwin->w_p_twk != NUL && string_to_key(curwin->w_p_twk, TRUE) == 0)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-/*
- * The 'termwinsize' option is changed.
- */
-    char *
-did_set_termwinsize(optset_T *args UNUSED)
-{
-    char_u	*p;
-
-    if (*curwin->w_p_tws == NUL)
-	return NULL;
-
-    p = skipdigits(curwin->w_p_tws);
-    if (p == curwin->w_p_tws
-	    || (*p != 'x' && *p != '*')
-	    || *skipdigits(p + 1) != NUL)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-# if defined(MSWIN) || defined(PROTO)
-/*
- * The 'termwintype' option is changed.
- */
-    char *
-did_set_termwintype(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_twt, p_twt_values, FALSE);
-}
-# endif
-#endif
-
-/*
- * The 'titlestring' option is changed.
- */
-    char *
-did_set_titlestring(optset_T *args)
-{
-    int flagval = 0;
-
-#ifdef FEAT_STL_OPT
-    flagval = STL_IN_TITLE;
-#endif
-    return parse_titleiconstring(args, flagval);
-}
-
-#if (defined(FEAT_TOOLBAR) && !defined(FEAT_GUI_MSWIN)) || defined(PROTO)
-/*
- * The 'toolbar' option is changed.
- */
-    char *
-did_set_toolbar(optset_T *args UNUSED)
-{
-    if (opt_strings_flags(p_toolbar, p_toolbar_values, &toolbar_flags,
-								TRUE) != OK)
-	return e_invalid_argument;
-
-    out_flush();
-    gui_mch_show_toolbar((toolbar_flags &
-		(TOOLBAR_TEXT | TOOLBAR_ICONS)) != 0);
-    return NULL;
-}
-#endif
-
-#if (defined(FEAT_TOOLBAR) && defined(FEAT_GUI_GTK)) || defined(PROTO)
-/*
- * The 'toolbariconsize' option is changed.  GTK+ 2 only.
- */
-    char *
-did_set_toolbariconsize(optset_T *args UNUSED)
-{
-    if (opt_strings_flags(p_tbis, p_tbis_values, &tbis_flags, FALSE) != OK)
-	return e_invalid_argument;
-
-    out_flush();
-    gui_mch_show_toolbar((toolbar_flags &
-		(TOOLBAR_TEXT | TOOLBAR_ICONS)) != 0);
-    return NULL;
-}
-#endif
-
-#if defined(UNIX) || defined(VMS) || defined(PROTO)
-/*
- * The 'ttymouse' option is changed.
- */
-    char *
-did_set_ttymouse(optset_T *args UNUSED)
-{
-    char *errmsg = NULL;
-
-    // Switch the mouse off before changing the escape sequences used for
-    // that.
-    mch_setmouse(FALSE);
-    if (opt_strings_flags(p_ttym, p_ttym_values, &ttym_flags, FALSE) != OK)
-	errmsg = e_invalid_argument;
-    else
-	check_mouse_termcode();
-    if (termcap_active)
-	setmouse();		// may switch it on again
-
-    return errmsg;
-}
-#endif
-
-#if defined(FEAT_VARTABS) || defined(PROTO)
-/*
- * The 'varsofttabstop' option is changed.
- */
-    char *
-did_set_varsofttabstop(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u *cp;
-
-    if (!((*varp)[0]) || ((*varp)[0] == '0' && !((*varp)[1])))
-	VIM_CLEAR(curbuf->b_p_vsts_array);
-    else
-    {
-	for (cp = *varp; *cp; ++cp)
-	{
-	    if (vim_isdigit(*cp))
-		continue;
-	    if (*cp == ',' && cp > *varp && *(cp-1) != ',')
-		continue;
-	    return e_invalid_argument;
-	}
-
-	int *oldarray = curbuf->b_p_vsts_array;
-	if (tabstop_set(*varp, &(curbuf->b_p_vsts_array)) == OK)
-	{
-	    if (oldarray)
-		vim_free(oldarray);
-	}
-	else
-	    return e_invalid_argument;
-    }
-
-    return NULL;
-}
-
-/*
- * The 'vartabstop' option is changed.
- */
-    char *
-did_set_vartabstop(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-    char_u *cp;
-
-    if (!((*varp)[0]) || ((*varp)[0] == '0' && !((*varp)[1])))
-	VIM_CLEAR(curbuf->b_p_vts_array);
-    else
-    {
-	for (cp = *varp; *cp; ++cp)
-	{
-	    if (vim_isdigit(*cp))
-		continue;
-	    if (*cp == ',' && cp > *varp && *(cp-1) != ',')
-		continue;
-	    return e_invalid_argument;
-	}
-
-	int *oldarray = curbuf->b_p_vts_array;
-
-	if (tabstop_set(*varp, &(curbuf->b_p_vts_array)) == OK)
-	{
-	    vim_free(oldarray);
-# ifdef FEAT_FOLDING
-	    if (foldmethodIsIndent(curwin))
-		foldUpdateAll(curwin);
-# endif
-	}
-	else
-	    return e_invalid_argument;
-    }
-
-    return NULL;
-}
-#endif
-
-/*
- * The 'verbosefile' option is changed.
- */
-    char *
-did_set_verbosefile(optset_T *args UNUSED)
-{
-    verbose_stop();
-    if (*p_vfile != NUL && verbose_open() == FAIL)
-	return e_invalid_argument;
-
-    return NULL;
-}
-
-#if defined(FEAT_SESSION) || defined(PROTO)
-/*
- * The 'viewoptions' option is changed.
- */
-    char *
-did_set_viewoptions(optset_T *args UNUSED)
-{
-    return did_set_opt_flags(p_vop, p_ssop_values, &vop_flags, TRUE);
-}
-#endif
-
-#if defined(FEAT_VIMINFO) || defined(PROTO)
-/*
- * The 'viminfo' option is changed.
- */
-    char *
-did_set_viminfo(optset_T *args)
-{
-    char_u	*s;
-    char	*errmsg = NULL;
-
-    for (s = p_viminfo; *s;)
-    {
-	// Check it's a valid character
-	if (vim_strchr((char_u *)"!\"%'/:<@cfhnrs", *s) == NULL)
-	{
-	    errmsg = illegal_char(args->os_errbuf, *s);
-	    break;
-	}
-	if (*s == 'n')	// name is always last one
-	    break;
-	else if (*s == 'r') // skip until next ','
-	{
-	    while (*++s && *s != ',')
-		;
-	}
-	else if (*s == '%')
-	{
-	    // optional number
-	    while (vim_isdigit(*++s))
-		;
-	}
-	else if (*s == '!' || *s == 'h' || *s == 'c')
-	    ++s;		// no extra chars
-	else		// must have a number
-	{
-	    while (vim_isdigit(*++s))
-		;
-
-	    if (!VIM_ISDIGIT(*(s - 1)))
-	    {
-		if (args->os_errbuf != NULL)
-		{
-		    sprintf(args->os_errbuf,
-			    _(e_missing_number_after_angle_str_angle),
-			    transchar_byte(*(s - 1)));
-		    errmsg = args->os_errbuf;
-		}
-		else
-		    errmsg = "";
-		break;
-	    }
-	}
-	if (*s == ',')
-	    ++s;
-	else if (*s)
-	{
-	    if (args->os_errbuf != NULL)
-		errmsg = e_missing_comma;
-	    else
-		errmsg = "";
-	    break;
-	}
-    }
-    if (*p_viminfo && errmsg == NULL && get_viminfo_parameter('\'') < 0)
-	errmsg = e_must_specify_a_value;
-
-    return errmsg;
-}
-#endif
-
-/*
- * The 'virtualedit' option is changed.
- */
-    char *
-did_set_virtualedit(optset_T *args)
-{
-    char_u		*ve = p_ve;
-    unsigned int	*flags = &ve_flags;
-
-    if (args->os_flags & OPT_LOCAL)
-    {
-	ve = curwin->w_p_ve;
-	flags = &curwin->w_ve_flags;
-    }
-
-    if ((args->os_flags & OPT_LOCAL) && *ve == NUL)
-	// make the local value empty: use the global value
-	*flags = 0;
-    else
-    {
-	if (opt_strings_flags(ve, p_ve_values, flags, TRUE) != OK)
-	    return e_invalid_argument;
-	else if (STRCMP(ve, args->os_oldval.string) != 0)
-	{
-	    // Recompute cursor position in case the new 've' setting
-	    // changes something.
-	    validate_virtcol();
-	    coladvance(curwin->w_virtcol);
-	}
-    }
-
-    return NULL;
-}
-
-/*
- * The 'whichwrap' option is changed.
- */
-    char *
-did_set_whichwrap(optset_T *args)
-{
-    char_u	**varp = (char_u **)args->os_varp;
-
-    return did_set_option_listflag(*varp, (char_u *)WW_ALL, args->os_errbuf);
-}
-
-/*
- * The 'wildmode' option is changed.
- */
-    char *
-did_set_wildmode(optset_T *args UNUSED)
-{
-    if (check_opt_wim() == FAIL)
-	return e_invalid_argument;
-    return NULL;
-}
-
-/*
- * The 'wildoptions' option is changed.
- */
-    char *
-did_set_wildoptions(optset_T *args UNUSED)
-{
-    return did_set_opt_strings(p_wop, p_wop_values, TRUE);
-}
-
-#if defined(FEAT_WAK) || defined(PROTO)
-/*
- * The 'winaltkeys' option is changed.
- */
-    char *
-did_set_winaltkeys(optset_T *args UNUSED)
-{
-    char *errmsg = NULL;
-
-    if (*p_wak == NUL || check_opt_strings(p_wak, p_wak_values, FALSE) != OK)
-	errmsg = e_invalid_argument;
-# ifdef FEAT_MENU
-#  if defined(FEAT_GUI_MOTIF)
-    else if (gui.in_use)
-	gui_motif_set_mnemonics(p_wak[0] == 'y' || p_wak[0] == 'm');
-#  elif defined(FEAT_GUI_GTK)
-    else if (gui.in_use)
-	gui_gtk_set_mnemonics(p_wak[0] == 'y' || p_wak[0] == 'm');
-#  endif
-# endif
-    return errmsg;
-}
-#endif
-
-/*
- * The 'wincolor' option is changed.
- */
-    char *
-did_set_wincolor(optset_T *args UNUSED)
-{
-#ifdef FEAT_TERMINAL
-    term_update_wincolor(curwin);
-#endif
-    return NULL;
-}
-
-#ifdef FEAT_SYN_HL
-/*
- * When the 'syntax' option is set, load the syntax of that name.
- */
-    static void
-do_syntax_autocmd(int value_changed)
-{
-    static int syn_recursive = 0;
-
-    ++syn_recursive;
-    // Only pass TRUE for "force" when the value changed or not used
-    // recursively, to avoid endless recurrence.
-    apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn, curbuf->b_fname,
-	    value_changed || syn_recursive == 1, curbuf);
-    curbuf->b_flags |= BF_SYN_SET;
-    --syn_recursive;
-}
-#endif
-
-/*
- * When the 'filetype' option is set, trigger the FileType autocommand.
- */
-    static void
-do_filetype_autocmd(char_u **varp, int opt_flags, int value_changed)
-{
-    // Skip this when called from a modeline and the filetype was already set
-    // to this value.
-    if ((opt_flags & OPT_MODELINE) && !value_changed)
-	return;
-
-    static int  ft_recursive = 0;
-    int	    secure_save = secure;
-
-    // Reset the secure flag, since the value of 'filetype' has
-    // been checked to be safe.
-    secure = 0;
-
-    ++ft_recursive;
-    did_filetype = TRUE;
-    // Only pass TRUE for "force" when the value changed or not
-    // used recursively, to avoid endless recurrence.
-    apply_autocmds(EVENT_FILETYPE, curbuf->b_p_ft, curbuf->b_fname,
-	    value_changed || ft_recursive == 1, curbuf);
-    --ft_recursive;
-    // Just in case the old "curbuf" is now invalid.
-    if (varp != &(curbuf->b_p_ft))
-	varp = NULL;
-
-    secure = secure_save;
-}
-
-#ifdef FEAT_SPELL
-/*
- * When the 'spelllang' option is set, source the spell/LANG.vim file in
- * 'runtimepath'.
- */
-    static void
-do_spelllang_source(void)
-{
-    char_u	fname[200];
-    char_u	*p;
-    char_u	*q = curwin->w_s->b_p_spl;
-
-    // Skip the first name if it is "cjk".
-    if (STRNCMP(q, "cjk,", 4) == 0)
-	q += 4;
-
-    // They could set 'spellcapcheck' depending on the language.  Use the first
-    // name in 'spelllang' up to '_region' or '.encoding'.
-    for (p = q; *p != NUL; ++p)
-	if (!ASCII_ISALNUM(*p) && *p != '-')
-	    break;
-    if (p > q)
-    {
-	vim_snprintf((char *)fname, 200, "spell/%.*s.vim",
-		(int)(p - q), q);
-	source_runtime(fname, DIP_ALL);
-    }
-}
-#endif
-
-/*
- * Handle string options that need some action to perform when changed.
- * The new value must be allocated.
- * Returns NULL for success, or an untranslated error message for an error.
- */
-    char *
-did_set_string_option(
-    int		opt_idx,		// index in options[] table
-    char_u	**varp,			// pointer to the option variable
-    char_u	*oldval,		// previous value of the option
-    char_u	*value,			// new value of the option
-    char	*errbuf,		// buffer for errors, or NULL
-    int		opt_flags,		// OPT_LOCAL and/or OPT_GLOBAL
-    int		*value_checked)		// value was checked to be safe, no
-					// need to set P_INSECURE
-{
-    char	*errmsg = NULL;
-    long_u	free_oldval = (get_option_flags(opt_idx) & P_ALLOCED);
-    opt_did_set_cb_T did_set_cb = get_option_did_set_cb(opt_idx);
-    optset_T	args;
-
-    // 'ttytype' is an alias for 'term'.  Both 'term' and 'ttytype' point to
-    // T_NAME.  If 'term' or 'ttytype' is modified, then use the index for the
-    // 'term' option.  Only set the P_ALLOCED flag on 'term'.
-    if (varp == &T_NAME)
-    {
-	opt_idx = findoption((char_u *)"term");
-	if (opt_idx >= 0)
-	{
-	    free_oldval = (get_option_flags(opt_idx) & P_ALLOCED);
-	    did_set_cb = get_option_did_set_cb(opt_idx);
-	}
-    }
-
-    CLEAR_FIELD(args);
-
-    // Disallow changing some options from secure mode
-    if ((secure
-#ifdef HAVE_SANDBOX
-		|| sandbox != 0
-#endif
-		) && (get_option_flags(opt_idx) & P_SECURE))
-	errmsg = e_not_allowed_here;
-    // Check for a "normal" directory or file name in some options.
-    else if (check_illegal_path_names(opt_idx, varp))
-	errmsg = e_invalid_argument;
-    else if (did_set_cb != NULL)
-    {
-	args.os_varp = (char_u *)varp;
-	args.os_idx = opt_idx;
-	args.os_flags = opt_flags;
-	args.os_oldval.string = oldval;
-	args.os_newval.string = value;
-	args.os_errbuf = errbuf;
-	// Invoke the option specific callback function to validate and apply
-	// the new option value.
-	errmsg = did_set_cb(&args);
-
-	// The 'keymap', 'filetype' and 'syntax' option callback functions
-	// may change the os_value_checked field.
-	*value_checked = args.os_value_checked;
-    }
-
-    // If an error is detected, restore the previous value.
-    if (errmsg != NULL)
-    {
-	free_string_option(*varp);
-	*varp = oldval;
-	// When resetting some values, need to act on it.
-	if (args.os_restore_chartab)
-	    (void)init_chartab();
-	if (varp == &p_hl)
-	    (void)highlight_changed();
-    }
-    else
-    {
-#ifdef FEAT_EVAL
-	// Remember where the option was set.
-	set_option_sctx_idx(opt_idx, opt_flags, current_sctx);
-#endif
-	// Free string options that are in allocated memory.
-	// Use "free_oldval", because recursiveness may change the flags under
-	// our fingers (esp. init_highlight()).
-	if (free_oldval)
-	    free_string_option(oldval);
-	set_option_flag(opt_idx, P_ALLOCED);
-
-	if ((opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0
-		&& is_global_local_option(opt_idx))
-	{
-	    // global option with local value set to use global value; free
-	    // the local value and make it empty
-	    char_u *p = get_option_varp_scope(opt_idx, OPT_LOCAL);
-	    free_string_option(*(char_u **)p);
-	    *(char_u **)p = empty_option;
-	}
-
-	// May set global value for local option.
-	else if (!(opt_flags & OPT_LOCAL) && opt_flags != OPT_GLOBAL)
-	    set_string_option_global(opt_idx, varp);
-
-	// Trigger the autocommand only after setting the flags.
-#ifdef FEAT_SYN_HL
-	if (varp == &(curbuf->b_p_syn))
-	    do_syntax_autocmd(args.os_value_changed);
-#endif
-	else if (varp == &(curbuf->b_p_ft))
-	    do_filetype_autocmd(varp, opt_flags, args.os_value_changed);
-#ifdef FEAT_SPELL
-	if (varp == &(curwin->w_s->b_p_spl))
-	    do_spelllang_source();
-#endif
-    }
-
-    if (varp == &p_mouse)
-    {
-	if (*p_mouse == NUL)
-	    mch_setmouse(FALSE);    // switch mouse off
-	else
-	    setmouse();		    // in case 'mouse' changed
-    }
-
-#if defined(FEAT_LUA) || defined(PROTO)
-    if (varp == &p_rtp)
-	update_package_paths_in_lua();
-#endif
-
-#if defined(FEAT_LINEBREAK)
-    // Changing Formatlistpattern when briopt includes the list setting:
-    // redraw
-    if ((varp == &p_flp || varp == &(curbuf->b_p_flp))
-	    && curwin->w_briopt_list)
-	redraw_all_later(UPD_NOT_VALID);
-#endif
-
-    if (curwin->w_curswant != MAXCOL
-		   && (get_option_flags(opt_idx) & (P_CURSWANT | P_RALL)) != 0)
-	curwin->w_set_curswant = TRUE;
-
-    if ((opt_flags & OPT_NO_REDRAW) == 0)
-    {
-#ifdef FEAT_GUI
-	// set when changing an option that only requires a redraw in the GUI
-	int	redraw_gui_only = FALSE;
-
-	if (varp == &p_go			// 'guioptions'
-		|| varp == &p_guifont		// 'guifont'
-# ifdef FEAT_GUI_TABLINE
-		|| varp == &p_gtl		// 'guitablabel'
-		|| varp == &p_gtt		// 'guitabtooltip'
-# endif
-# ifdef FEAT_XFONTSET
-		|| varp == &p_guifontset	// 'guifontset'
-# endif
-		|| varp == &p_guifontwide	// 'guifontwide'
-# ifdef FEAT_GUI_GTK
-		|| varp == &p_guiligatures	// 'guiligatures'
-# endif
-	    )
-	    redraw_gui_only = TRUE;
-
-	// check redraw when it's not a GUI option or the GUI is active.
-	if (!redraw_gui_only || gui.in_use)
-#endif
-	    check_redraw(get_option_flags(opt_idx));
-    }
-
-#if defined(FEAT_VTP) && defined(FEAT_TERMGUICOLORS)
-    if (args.os_did_swaptcap)
-    {
-	set_termname((char_u *)"win32");
-	init_highlight(TRUE, FALSE);
-    }
-#endif
-
-    return errmsg;
-}
-
-/*
- * Check an option that can be a range of string values.
- *
- * Return OK for correct value, FAIL otherwise.
- * Empty is always OK.
- */
-    static int
-check_opt_strings(
-    char_u	*val,
-    char	**values,
-    int		list)	    // when TRUE: accept a list of values
-{
-    return opt_strings_flags(val, values, NULL, list);
-}
-
-/*
- * Handle an option that can be a range of string values.
- * Set a flag in "*flagp" for each string present.
- *
- * Return OK for correct value, FAIL otherwise.
- * Empty is always OK.
- */
-    static int
-opt_strings_flags(
-    char_u	*val,		// new value
-    char	**values,	// array of valid string values
-    unsigned	*flagp,
-    int		list)		// when TRUE: accept a list of values
-{
-    int		i;
-    int		len;
-    unsigned	new_flags = 0;
-
-    while (*val)
-    {
-	for (i = 0; ; ++i)
-	{
-	    if (values[i] == NULL)	// val not found in values[]
-		return FAIL;
-
-	    len = (int)STRLEN(values[i]);
-	    if (STRNCMP(values[i], val, len) == 0
-		    && ((list && val[len] == ',') || val[len] == NUL))
-	    {
-		val += len + (val[len] == ',');
-		new_flags |= (1 << i);
-		break;		// check next item in val list
-	    }
-	}
-    }
-    if (flagp != NULL)
-	*flagp = new_flags;
-
-    return OK;
-}
-
-/*
- * return OK if "p" is a valid fileformat name, FAIL otherwise.
- */
-    int
-check_ff_value(char_u *p)
-{
-    return check_opt_strings(p, p_ff_values, FALSE);
-}
-
-/*
- * Save the actual shortmess Flags and clear them temporarily to avoid that
- * file messages overwrites any output from the following commands.
- *
- * Caller must make sure to first call save_clear_shm_value() and then
- * restore_shm_value() exactly the same number of times.
- */
-    void
-save_clear_shm_value(void)
-{
-    if (STRLEN(p_shm) >= SHM_LEN)
-    {
-	iemsg(e_internal_error_shortmess_too_long);
-	return;
-    }
-
-    if (++set_shm_recursive == 1)
-    {
-	STRCPY(shm_buf, p_shm);
-	set_option_value_give_err((char_u *)"shm", 0L, (char_u *)"", 0);
-    }
-}
-
-/*
- * Restore the shortmess Flags set from the save_clear_shm_value() function.
- */
-    void
-restore_shm_value(void)
-{
-    if (--set_shm_recursive == 0)
-    {
-	set_option_value_give_err((char_u *)"shm", 0L, shm_buf, 0);
-	vim_memset(shm_buf, 0, SHM_LEN);
-    }
-}
+/* vi:set ts=8 sts=4 sw=4 noet:
+ *
+ * VIM - Vi IMproved	by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ * See README.txt for an overview of the Vim source code.
+ */
+
+/*
+ * optionstr.c: Functions related to string options
+ */
+
+#include "vim.h"
+
+static char_u shm_buf[SHM_LEN];
+static int set_shm_recursive = 0;
+
+static char *(p_ambw_values[]) = {"single", "double", NULL};
+static char *(p_bg_values[]) = {"light", "dark", NULL};
+static char *(p_bkc_values[]) = {"yes", "auto", "no", "breaksymlink", "breakhardlink", NULL};
+static char *(p_bo_values[]) = {"all", "backspace", "cursor", "complete",
+				 "copy", "ctrlg", "error", "esc", "ex",
+				 "hangul", "insertmode", "lang", "mess",
+				 "showmatch", "operator", "register", "shell",
+				 "spell", "term", "wildmode", NULL};
+static char *(p_nf_values[]) = {"bin", "octal", "hex", "alpha", "unsigned", NULL};
+static char *(p_ff_values[]) = {FF_UNIX, FF_DOS, FF_MAC, NULL};
+#ifdef FEAT_CRYPT
+static char *(p_cm_values[]) = {"zip", "blowfish", "blowfish2",
+ # ifdef FEAT_SODIUM
+    "xchacha20", "xchacha20v2",
+ # endif
+    NULL};
+#endif
+static char *(p_cmp_values[]) = {"internal", "keepascii", NULL};
+static char *(p_dy_values[]) = {"lastline", "truncate", "uhex", NULL};
+#ifdef FEAT_FOLDING
+static char *(p_fdo_values[]) = {"all", "block", "hor", "mark", "percent",
+				 "quickfix", "search", "tag", "insert",
+				 "undo", "jump", NULL};
+#endif
+#ifdef FEAT_SESSION
+// Also used for 'viewoptions'!  Keep in sync with SSOP_ flags.
+static char *(p_ssop_values[]) = {"buffers", "winpos", "resize", "winsize",
+    "localoptions", "options", "help", "blank", "globals", "slash", "unix",
+    "sesdir", "curdir", "folds", "cursor", "tabpages", "terminal", "skiprtp",
+    NULL};
+#endif
+// Keep in sync with SWB_ flags in option.h
+static char *(p_swb_values[]) = {"useopen", "usetab", "split", "newtab", "vsplit", "uselast", NULL};
+static char *(p_spk_values[]) = {"cursor", "screen", "topline", NULL};
+static char *(p_tc_values[]) = {"followic", "ignore", "match", "followscs", "smart", NULL};
+#if defined(FEAT_TOOLBAR) && !defined(FEAT_GUI_MSWIN)
+static char *(p_toolbar_values[]) = {"text", "icons", "tooltips", "horiz", NULL};
+#endif
+#if defined(FEAT_TOOLBAR) && defined(FEAT_GUI_GTK)
+static char *(p_tbis_values[]) = {"tiny", "small", "medium", "large", "huge", "giant", NULL};
+#endif
+#if defined(UNIX) || defined(VMS)
+static char *(p_ttym_values[]) = {"xterm", "xterm2", "dec", "netterm", "jsbterm", "pterm", "urxvt", "sgr", NULL};
+#endif
+static char *(p_ve_values[]) = {"block", "insert", "all", "onemore", "none", "NONE", NULL};
+static char *(p_wop_values[]) = {"fuzzy", "tagfile", "pum", NULL};
+#ifdef FEAT_WAK
+static char *(p_wak_values[]) = {"yes", "menu", "no", NULL};
+#endif
+static char *(p_mousem_values[]) = {"extend", "popup", "popup_setpos", "mac", NULL};
+static char *(p_sel_values[]) = {"inclusive", "exclusive", "old", NULL};
+static char *(p_slm_values[]) = {"mouse", "key", "cmd", NULL};
+static char *(p_km_values[]) = {"startsel", "stopsel", NULL};
+#ifdef FEAT_BROWSE
+static char *(p_bsdir_values[]) = {"current", "last", "buffer", NULL};
+#endif
+static char *(p_scbopt_values[]) = {"ver", "hor", "jump", NULL};
+static char *(p_debug_values[]) = {"msg", "throw", "beep", NULL};
+static char *(p_ead_values[]) = {"both", "ver", "hor", NULL};
+static char *(p_buftype_values[]) = {"nofile", "nowrite", "quickfix", "help", "terminal", "acwrite", "prompt", "popup", NULL};
+static char *(p_bufhidden_values[]) = {"hide", "unload", "delete", "wipe", NULL};
+static char *(p_bs_values[]) = {"indent", "eol", "start", "nostop", NULL};
+#ifdef FEAT_FOLDING
+static char *(p_fdm_values[]) = {"manual", "expr", "marker", "indent", "syntax",
+# ifdef FEAT_DIFF
+				"diff",
+# endif
+				NULL};
+static char *(p_fcl_values[]) = {"all", NULL};
+#endif
+static char *(p_cot_values[]) = {"menu", "menuone", "longest", "preview", "popup", "popuphidden", "noinsert", "noselect", NULL};
+#ifdef BACKSLASH_IN_FILENAME
+static char *(p_csl_values[]) = {"slash", "backslash", NULL};
+#endif
+#ifdef FEAT_SIGNS
+static char *(p_scl_values[]) = {"yes", "no", "auto", "number", NULL};
+#endif
+#if defined(MSWIN) && defined(FEAT_TERMINAL)
+static char *(p_twt_values[]) = {"winpty", "conpty", "", NULL};
+#endif
+static char *(p_sloc_values[]) = {"last", "statusline", "tabline", NULL};
+static char *(p_sws_values[]) = {"fsync", "sync", NULL};
+
+static int check_opt_strings(char_u *val, char **values, int list);
+static int opt_strings_flags(char_u *val, char **values, unsigned *flagp, int list);
+
+/*
+ * After setting various option values: recompute variables that depend on
+ * option values.
+ */
+    void
+didset_string_options(void)
+{
+    (void)opt_strings_flags(p_cmp, p_cmp_values, &cmp_flags, TRUE);
+    (void)opt_strings_flags(p_bkc, p_bkc_values, &bkc_flags, TRUE);
+    (void)opt_strings_flags(p_bo, p_bo_values, &bo_flags, TRUE);
+#ifdef FEAT_SESSION
+    (void)opt_strings_flags(p_ssop, p_ssop_values, &ssop_flags, TRUE);
+    (void)opt_strings_flags(p_vop, p_ssop_values, &vop_flags, TRUE);
+#endif
+#ifdef FEAT_FOLDING
+    (void)opt_strings_flags(p_fdo, p_fdo_values, &fdo_flags, TRUE);
+#endif
+    (void)opt_strings_flags(p_dy, p_dy_values, &dy_flags, TRUE);
+    (void)opt_strings_flags(p_tc, p_tc_values, &tc_flags, FALSE);
+    (void)opt_strings_flags(p_ve, p_ve_values, &ve_flags, TRUE);
+#if defined(UNIX) || defined(VMS)
+    (void)opt_strings_flags(p_ttym, p_ttym_values, &ttym_flags, FALSE);
+#endif
+#if defined(FEAT_TOOLBAR) && !defined(FEAT_GUI_MSWIN)
+    (void)opt_strings_flags(p_toolbar, p_toolbar_values, &toolbar_flags, TRUE);
+#endif
+#if defined(FEAT_TOOLBAR) && defined(FEAT_GUI_GTK)
+    (void)opt_strings_flags(p_tbis, p_tbis_values, &tbis_flags, FALSE);
+#endif
+    (void)opt_strings_flags(p_swb, p_swb_values, &swb_flags, TRUE);
+}
+
+#if defined(FEAT_EVAL) || defined(PROTO)
+/*
+ * Trigger the OptionSet autocommand.
+ * "opt_idx"	is the index of the option being set.
+ * "opt_flags"	can be OPT_LOCAL etc.
+ * "oldval"	the old value
+ *  "oldval_l"  the old local value (only non-NULL if global and local value
+ *		are set)
+ * "oldval_g"   the old global value (only non-NULL if global and local value
+ *		are set)
+ * "newval"	the new value
+ */
+    void
+trigger_optionset_string(
+	int	opt_idx,
+	int	opt_flags,
+	char_u  *oldval,
+	char_u  *oldval_l,
+	char_u  *oldval_g,
+	char_u  *newval)
+{
+    // Don't do this recursively.
+    if (oldval == NULL || newval == NULL
+				    || *get_vim_var_str(VV_OPTION_TYPE) != NUL)
+	return;
+
+    char_u buf_type[7];
+
+    sprintf((char *)buf_type, "%s",
+	    (opt_flags & OPT_LOCAL) ? "local" : "global");
+    set_vim_var_string(VV_OPTION_OLD, oldval, -1);
+    set_vim_var_string(VV_OPTION_NEW, newval, -1);
+    set_vim_var_string(VV_OPTION_TYPE, buf_type, -1);
+    if (opt_flags & OPT_LOCAL)
+    {
+	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"setlocal", -1);
+	set_vim_var_string(VV_OPTION_OLDLOCAL, oldval, -1);
+    }
+    if (opt_flags & OPT_GLOBAL)
+    {
+	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"setglobal", -1);
+	set_vim_var_string(VV_OPTION_OLDGLOBAL, oldval, -1);
+    }
+    if ((opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0)
+    {
+	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"set", -1);
+	set_vim_var_string(VV_OPTION_OLDLOCAL, oldval_l, -1);
+	set_vim_var_string(VV_OPTION_OLDGLOBAL, oldval_g, -1);
+    }
+    if (opt_flags & OPT_MODELINE)
+    {
+	set_vim_var_string(VV_OPTION_COMMAND, (char_u *)"modeline", -1);
+	set_vim_var_string(VV_OPTION_OLDLOCAL, oldval, -1);
+    }
+    apply_autocmds(EVENT_OPTIONSET,
+	    get_option_fullname(opt_idx), NULL, FALSE,
+	    NULL);
+    reset_v_option_vars();
+}
+#endif
+
+    static char *
+illegal_char(char *errbuf, int c)
+{
+    if (errbuf == NULL)
+	return "";
+    sprintf((char *)errbuf, _(e_illegal_character_str), (char *)transchar(c));
+    return errbuf;
+}
+
+/*
+ * Check string options in a buffer for NULL value.
+ */
+    void
+check_buf_options(buf_T *buf)
+{
+    check_string_option(&buf->b_p_bh);
+    check_string_option(&buf->b_p_bt);
+    check_string_option(&buf->b_p_fenc);
+    check_string_option(&buf->b_p_ff);
+#ifdef FEAT_FIND_ID
+    check_string_option(&buf->b_p_def);
+    check_string_option(&buf->b_p_inc);
+# ifdef FEAT_EVAL
+    check_string_option(&buf->b_p_inex);
+# endif
+#endif
+#if defined(FEAT_EVAL)
+    check_string_option(&buf->b_p_inde);
+    check_string_option(&buf->b_p_indk);
+#endif
+#if defined(FEAT_BEVAL) && defined(FEAT_EVAL)
+    check_string_option(&buf->b_p_bexpr);
+#endif
+#if defined(FEAT_CRYPT)
+    check_string_option(&buf->b_p_cm);
+#endif
+    check_string_option(&buf->b_p_fp);
+#if defined(FEAT_EVAL)
+    check_string_option(&buf->b_p_fex);
+#endif
+#ifdef FEAT_CRYPT
+    check_string_option(&buf->b_p_key);
+#endif
+    check_string_option(&buf->b_p_kp);
+    check_string_option(&buf->b_p_mps);
+    check_string_option(&buf->b_p_fo);
+    check_string_option(&buf->b_p_flp);
+    check_string_option(&buf->b_p_isk);
+    check_string_option(&buf->b_p_com);
+#ifdef FEAT_FOLDING
+    check_string_option(&buf->b_p_cms);
+#endif
+    check_string_option(&buf->b_p_nf);
+    check_string_option(&buf->b_p_qe);
+#ifdef FEAT_SYN_HL
+    check_string_option(&buf->b_p_syn);
+    check_string_option(&buf->b_s.b_syn_isk);
+#endif
+#ifdef FEAT_SPELL
+    check_string_option(&buf->b_s.b_p_spc);
+    check_string_option(&buf->b_s.b_p_spf);
+    check_string_option(&buf->b_s.b_p_spl);
+    check_string_option(&buf->b_s.b_p_spo);
+#endif
+    check_string_option(&buf->b_p_sua);
+    check_string_option(&buf->b_p_cink);
+    check_string_option(&buf->b_p_cino);
+    check_string_option(&buf->b_p_cinsd);
+    parse_cino(buf);
+    check_string_option(&buf->b_p_lop);
+    check_string_option(&buf->b_p_ft);
+    check_string_option(&buf->b_p_cinw);
+    check_string_option(&buf->b_p_cpt);
+#ifdef FEAT_COMPL_FUNC
+    check_string_option(&buf->b_p_cfu);
+    check_string_option(&buf->b_p_ofu);
+    check_string_option(&buf->b_p_tsrfu);
+#endif
+#ifdef FEAT_EVAL
+    check_string_option(&buf->b_p_tfu);
+#endif
+#ifdef FEAT_KEYMAP
+    check_string_option(&buf->b_p_keymap);
+#endif
+#ifdef FEAT_QUICKFIX
+    check_string_option(&buf->b_p_gp);
+    check_string_option(&buf->b_p_mp);
+    check_string_option(&buf->b_p_efm);
+#endif
+    check_string_option(&buf->b_p_ep);
+    check_string_option(&buf->b_p_path);
+    check_string_option(&buf->b_p_tags);
+    check_string_option(&buf->b_p_tc);
+    check_string_option(&buf->b_p_dict);
+    check_string_option(&buf->b_p_tsr);
+    check_string_option(&buf->b_p_lw);
+    check_string_option(&buf->b_p_bkc);
+    check_string_option(&buf->b_p_menc);
+#ifdef FEAT_VARTABS
+    check_string_option(&buf->b_p_vsts);
+    check_string_option(&buf->b_p_vts);
+#endif
+}
+
+/*
+ * Free the string allocated for an option.
+ * Checks for the string being empty_option. This may happen if we're out of
+ * memory, vim_strsave() returned NULL, which was replaced by empty_option by
+ * check_options().
+ * Does NOT check for P_ALLOCED flag!
+ */
+    void
+free_string_option(char_u *p)
+{
+    if (p != empty_option)
+	vim_free(p);
+}
+
+    void
+clear_string_option(char_u **pp)
+{
+    if (*pp != empty_option)
+	vim_free(*pp);
+    *pp = empty_option;
+}
+
+    void
+check_string_option(char_u **pp)
+{
+    if (*pp == NULL)
+	*pp = empty_option;
+}
+
+/*
+ * Set global value for string option when it's a local option.
+ */
+    static void
+set_string_option_global(
+    int		opt_idx,	// option index
+    char_u	**varp)		// pointer to option variable
+{
+    char_u	**p, *s;
+
+    // the global value is always allocated
+    if (is_window_local_option(opt_idx))
+	p = (char_u **)GLOBAL_WO(varp);
+    else
+	p = (char_u **)get_option_var(opt_idx);
+    if (!is_global_option(opt_idx)
+	    && p != varp
+	    && (s = vim_strsave(*varp)) != NULL)
+    {
+	free_string_option(*p);
+	*p = s;
+    }
+}
+
+/*
+ * Set a string option to a new value (without checking the effect).
+ * The string is copied into allocated memory.
+ * if ("opt_idx" == -1) "name" is used, otherwise "opt_idx" is used.
+ * When "set_sid" is zero set the scriptID to current_sctx.sc_sid.  When
+ * "set_sid" is SID_NONE don't set the scriptID.  Otherwise set the scriptID to
+ * "set_sid".
+ */
+    void
+set_string_option_direct(
+    char_u	*name,
+    int		opt_idx,
+    char_u	*val,
+    int		opt_flags,	// OPT_FREE, OPT_LOCAL and/or OPT_GLOBAL
+    int		set_sid UNUSED)
+{
+    char_u	*s;
+    char_u	**varp;
+    int		both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
+    int		idx = opt_idx;
+
+    if (idx == -1)		// use name
+    {
+	idx = findoption(name);
+	if (idx < 0)	// not found (should not happen)
+	{
+	    semsg(_(e_internal_error_str), "set_string_option_direct()");
+	    siemsg("For option %s", name);
+	    return;
+	}
+    }
+
+    if (is_hidden_option(idx))		// can't set hidden option
+	return;
+
+    s = vim_strsave(val);
+    if (s == NULL)
+	return;
+
+    varp = (char_u **)get_option_varp_scope(idx,
+	    both ? OPT_LOCAL : opt_flags);
+    if ((opt_flags & OPT_FREE) && (get_option_flags(idx) & P_ALLOCED))
+	free_string_option(*varp);
+    *varp = s;
+
+    // For buffer/window local option may also set the global value.
+    if (both)
+	set_string_option_global(idx, varp);
+
+    set_option_flag(idx, P_ALLOCED);
+
+    // When setting both values of a global option with a local value,
+    // make the local value empty, so that the global value is used.
+    if (is_global_local_option(idx) && both)
+    {
+	free_string_option(*varp);
+	*varp = empty_option;
+    }
+# ifdef FEAT_EVAL
+    if (set_sid != SID_NONE)
+    {
+	sctx_T script_ctx;
+
+	if (set_sid == 0)
+	    script_ctx = current_sctx;
+	else
+	{
+	    script_ctx.sc_sid = set_sid;
+	    script_ctx.sc_seq = 0;
+	    script_ctx.sc_lnum = 0;
+	    script_ctx.sc_version = 1;
+	}
+	set_option_sctx_idx(idx, opt_flags, script_ctx);
+    }
+# endif
+}
+
+#if defined(FEAT_PROP_POPUP) || \
+    (defined(FEAT_DIFF) && defined(FEAT_FOLDING)) || defined(PROTO)
+/*
+ * Like set_string_option_direct(), but for a window-local option in "wp".
+ * Blocks autocommands to avoid the old curwin becoming invalid.
+ */
+    void
+set_string_option_direct_in_win(
+	win_T		*wp,
+	char_u		*name,
+	int		opt_idx,
+	char_u		*val,
+	int		opt_flags,
+	int		set_sid)
+{
+    win_T	*save_curwin = curwin;
+
+    block_autocmds();
+    curwin = wp;
+    curbuf = curwin->w_buffer;
+    set_string_option_direct(name, opt_idx, val, opt_flags, set_sid);
+    curwin = save_curwin;
+    curbuf = curwin->w_buffer;
+    unblock_autocmds();
+}
+#endif
+
+#if defined(FEAT_PROP_POPUP) || defined(PROTO)
+/*
+ * Like set_string_option_direct(), but for a buffer-local option in "buf".
+ * Blocks autocommands to avoid the old curbuf becoming invalid.
+ */
+    void
+set_string_option_direct_in_buf(
+	buf_T		*buf,
+	char_u		*name,
+	int		opt_idx,
+	char_u		*val,
+	int		opt_flags,
+	int		set_sid)
+{
+    buf_T	*save_curbuf = curbuf;
+
+    block_autocmds();
+    curbuf = buf;
+    curwin->w_buffer = curbuf;
+    set_string_option_direct(name, opt_idx, val, opt_flags, set_sid);
+    curbuf = save_curbuf;
+    curwin->w_buffer = curbuf;
+    unblock_autocmds();
+}
+#endif
+
+/*
+ * Set a string option to a new value, and handle the effects.
+ *
+ * Returns NULL on success or an untranslated error message on error.
+ */
+    char *
+set_string_option(
+    int		opt_idx,
+    char_u	*value,
+    int		opt_flags,	// OPT_LOCAL and/or OPT_GLOBAL
+    char	*errbuf)
+{
+    char_u	*s;
+    char_u	**varp;
+    char_u	*oldval;
+#if defined(FEAT_EVAL)
+    char_u	*oldval_l = NULL;
+    char_u	*oldval_g = NULL;
+    char_u	*saved_oldval = NULL;
+    char_u	*saved_oldval_l = NULL;
+    char_u	*saved_oldval_g = NULL;
+    char_u	*saved_newval = NULL;
+#endif
+    char	*errmsg = NULL;
+    int		value_checked = FALSE;
+
+    if (is_hidden_option(opt_idx))	// don't set hidden option
+	return NULL;
+
+    s = vim_strsave(value == NULL ? (char_u *)"" : value);
+    if (s == NULL)
+	return NULL;
+
+    varp = (char_u **)get_option_varp_scope(opt_idx,
+	    (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0
+	    ? (is_global_local_option(opt_idx)
+		? OPT_GLOBAL : OPT_LOCAL)
+	    : opt_flags);
+    oldval = *varp;
+#if defined(FEAT_EVAL)
+    if ((opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0)
+    {
+	oldval_l = *(char_u **)get_option_varp_scope(opt_idx, OPT_LOCAL);
+	oldval_g = *(char_u **)get_option_varp_scope(opt_idx, OPT_GLOBAL);
+    }
+#endif
+    *varp = s;
+
+#if defined(FEAT_EVAL)
+    if (!starting
+# ifdef FEAT_CRYPT
+	    && !is_crypt_key_option(opt_idx)
+# endif
+       )
+    {
+	if (oldval_l != NULL)
+	    saved_oldval_l = vim_strsave(oldval_l);
+	if (oldval_g != NULL)
+	    saved_oldval_g = vim_strsave(oldval_g);
+	saved_oldval = vim_strsave(oldval);
+	saved_newval = vim_strsave(s);
+    }
+#endif
+    if ((errmsg = did_set_string_option(opt_idx, varp, oldval, value, errbuf,
+		    opt_flags, &value_checked)) == NULL)
+	did_set_option(opt_idx, opt_flags, TRUE, value_checked);
+
+#if defined(FEAT_EVAL)
+    // call autocommand after handling side effects
+    if (errmsg == NULL)
+	trigger_optionset_string(opt_idx, opt_flags,
+		saved_oldval, saved_oldval_l,
+		saved_oldval_g, saved_newval);
+    vim_free(saved_oldval);
+    vim_free(saved_oldval_l);
+    vim_free(saved_oldval_g);
+    vim_free(saved_newval);
+#endif
+    return errmsg;
+}
+
+/*
+ * Return TRUE if "val" is a valid 'filetype' name.
+ * Also used for 'syntax' and 'keymap'.
+ */
+    static int
+valid_filetype(char_u *val)
+{
+    return valid_name(val, ".-_");
+}
+
+#ifdef FEAT_STL_OPT
+/*
+ * Check validity of options with the 'statusline' format.
+ * Return an untranslated error message or NULL.
+ */
+    static char *
+check_stl_option(char_u *s)
+{
+    int		groupdepth = 0;
+    static char errbuf[80];
+
+    while (*s)
+    {
+	// Check for valid keys after % sequences
+	while (*s && *s != '%')
+	    s++;
+	if (!*s)
+	    break;
+	s++;
+	if (*s == '%' || *s == STL_TRUNCMARK || *s == STL_SEPARATE)
+	{
+	    s++;
+	    continue;
+	}
+	if (*s == ')')
+	{
+	    s++;
+	    if (--groupdepth < 0)
+		break;
+	    continue;
+	}
+	if (*s == '-')
+	    s++;
+	while (VIM_ISDIGIT(*s))
+	    s++;
+	if (*s == STL_USER_HL)
+	    continue;
+	if (*s == '.')
+	{
+	    s++;
+	    while (*s && VIM_ISDIGIT(*s))
+		s++;
+	}
+	if (*s == '(')
+	{
+	    groupdepth++;
+	    continue;
+	}
+	if (vim_strchr(STL_ALL, *s) == NULL)
+	{
+	    return illegal_char(errbuf, *s);
+	}
+	if (*s == '{')
+	{
+	    int reevaluate = (*++s == '%');
+
+	    if (reevaluate && *++s == '}')
+		// "}" is not allowed immediately after "%{%"
+		return illegal_char(errbuf, '}');
+	    while ((*s != '}' || (reevaluate && s[-1] != '%')) && *s)
+		s++;
+	    if (*s != '}')
+		return e_unclosed_expression_sequence;
+	}
+    }
+    if (groupdepth != 0)
+	return e_unbalanced_groups;
+    return NULL;
+}
+#endif
+
+/*
+ * Check for a "normal" directory or file name in some options.  Disallow a
+ * path separator (slash and/or backslash), wildcards and characters that are
+ * often illegal in a file name. Be more permissive if "secure" is off.
+ */
+    static int
+check_illegal_path_names(int opt_idx, char_u **varp)
+{
+    return (((get_option_flags(opt_idx) & P_NFNAME)
+		&& vim_strpbrk(*varp, (char_u *)(secure
+			? "/\\*?[|;&<>\r\n" : "/\\*?[<>\r\n")) != NULL)
+	    || ((get_option_flags(opt_idx) & P_NDNAME)
+		&& vim_strpbrk(*varp, (char_u *)"*?[|;&<>\r\n") != NULL));
+}
+
+/*
+ * An option that accepts a list of flags is changed.
+ * e.g. 'viewoptions', 'switchbuf', 'casemap', etc.
+ */
+    static char *
+did_set_opt_flags(char_u *val, char **values, unsigned *flagp, int list)
+{
+    if (opt_strings_flags(val, values, flagp, list) == FAIL)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * An option that accepts a list of string values is changed.
+ * e.g. 'nrformats', 'scrollopt', 'wildoptions', etc.
+ */
+    static char *
+did_set_opt_strings(char_u *val, char **values, int list)
+{
+    return did_set_opt_flags(val, values, NULL, list);
+}
+
+/*
+ * An option which is a list of flags is set.  Valid values are in 'flags'.
+ */
+    static char *
+did_set_option_listflag(char_u *val, char_u *flags, char *errbuf)
+{
+    char_u	*s;
+
+    for (s = val; *s; ++s)
+	if (vim_strchr(flags, *s) == NULL)
+	    return illegal_char(errbuf, *s);
+
+    return NULL;
+}
+
+/*
+ * The 'ambiwidth' option is changed.
+ */
+    char *
+did_set_ambiwidth(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_ambw, p_ambw_values, FALSE) != OK)
+	return e_invalid_argument;
+
+    return check_chars_options();
+}
+
+/*
+ * The 'background' option is changed.
+ */
+    char *
+did_set_background(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_bg, p_bg_values, FALSE) == FAIL)
+	return e_invalid_argument;
+
+#ifdef FEAT_EVAL
+    int dark = (*p_bg == 'd');
+#endif
+
+    init_highlight(FALSE, FALSE);
+
+#ifdef FEAT_EVAL
+    if (dark != (*p_bg == 'd')
+	    && get_var_value((char_u *)"g:colors_name") != NULL)
+    {
+	// The color scheme must have set 'background' back to another
+	// value, that's not what we want here.  Disable the color
+	// scheme and set the colors again.
+	do_unlet((char_u *)"g:colors_name", TRUE);
+	free_string_option(p_bg);
+	p_bg = vim_strsave((char_u *)(dark ? "dark" : "light"));
+	check_string_option(&p_bg);
+	init_highlight(FALSE, FALSE);
+    }
+#endif
+#ifdef FEAT_TERMINAL
+    term_update_colors_all();
+#endif
+
+    return NULL;
+}
+
+/*
+ * The 'backspace' option is changed.
+ */
+    char *
+did_set_backspace(optset_T *args UNUSED)
+{
+    if (VIM_ISDIGIT(*p_bs))
+    {
+	if (*p_bs > '3' || p_bs[1] != NUL)
+	    return e_invalid_argument;
+    }
+    else if (check_opt_strings(p_bs, p_bs_values, TRUE) != OK)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * The 'backupcopy' option is changed.
+ */
+    char *
+did_set_backupcopy(optset_T *args)
+{
+    char_u		*bkc = p_bkc;
+    unsigned int	*flags = &bkc_flags;
+    char		*errmsg = NULL;
+
+    if (args->os_flags & OPT_LOCAL)
+    {
+	bkc = curbuf->b_p_bkc;
+	flags = &curbuf->b_bkc_flags;
+    }
+
+    if ((args->os_flags & OPT_LOCAL) && *bkc == NUL)
+	// make the local value empty: use the global value
+	*flags = 0;
+    else
+    {
+	if (opt_strings_flags(bkc, p_bkc_values, flags, TRUE) != OK)
+	    errmsg = e_invalid_argument;
+	if ((((int)*flags & BKC_AUTO) != 0)
+		+ (((int)*flags & BKC_YES) != 0)
+		+ (((int)*flags & BKC_NO) != 0) != 1)
+	{
+	    // Must have exactly one of "auto", "yes"  and "no".
+	    (void)opt_strings_flags(args->os_oldval.string, p_bkc_values,
+								  flags, TRUE);
+	    errmsg = e_invalid_argument;
+	}
+    }
+
+    return errmsg;
+}
+
+/*
+ * The 'backupext' or the 'patchmode' option is changed.
+ */
+    char *
+did_set_backupext_or_patchmode(optset_T *args UNUSED)
+{
+    if (STRCMP(*p_bex == '.' ? p_bex + 1 : p_bex,
+		*p_pm == '.' ? p_pm + 1 : p_pm) == 0)
+	return e_backupext_and_patchmode_are_equal;
+
+    return NULL;
+}
+
+/*
+ * The 'belloff' option is changed.
+ */
+    char *
+did_set_belloff(optset_T *args UNUSED)
+{
+    return did_set_opt_flags(p_bo, p_bo_values, &bo_flags, TRUE);
+}
+
+#if defined(FEAT_LINEBREAK) || defined(PROTO)
+/*
+ * The 'breakindentopt' option is changed.
+ */
+    char *
+did_set_breakindentopt(optset_T *args UNUSED)
+{
+    char *errmsg = NULL;
+
+    if (briopt_check(curwin) == FAIL)
+	errmsg = e_invalid_argument;
+    // list setting requires a redraw
+    if (curwin->w_briopt_list)
+	redraw_all_later(UPD_NOT_VALID);
+
+    return errmsg;
+}
+#endif
+
+#if defined(FEAT_BROWSE) || defined(PROTO)
+/*
+ * The 'browsedir' option is changed.
+ */
+    char *
+did_set_browsedir(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_bsdir, p_bsdir_values, FALSE) != OK
+	    && !mch_isdir(p_bsdir))
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'bufhidden' option is changed.
+ */
+    char *
+did_set_bufhidden(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(curbuf->b_p_bh, p_bufhidden_values, FALSE);
+}
+
+/*
+ * The 'buftype' option is changed.
+ */
+    char *
+did_set_buftype(optset_T *args UNUSED)
+{
+    if (check_opt_strings(curbuf->b_p_bt, p_buftype_values, FALSE) != OK)
+	return e_invalid_argument;
+
+    if (curwin->w_status_height)
+    {
+	curwin->w_redr_status = TRUE;
+	redraw_later(UPD_VALID);
+    }
+    curbuf->b_help = (curbuf->b_p_bt[0] == 'h');
+    redraw_titles();
+
+    return NULL;
+}
+
+/*
+ * The 'casemap' option is changed.
+ */
+    char *
+did_set_casemap(optset_T *args UNUSED)
+{
+    return did_set_opt_flags(p_cmp, p_cmp_values, &cmp_flags, TRUE);
+}
+
+/*
+ * The global 'listchars' or 'fillchars' option is changed.
+ */
+    static char *
+did_set_global_listfillchars(char_u *val, int opt_lcs, int opt_flags)
+{
+    char	*errmsg = NULL;
+    char_u	**local_ptr = opt_lcs ? &curwin->w_p_lcs : &curwin->w_p_fcs;
+
+    // only apply the global value to "curwin" when it does not have a
+    // local value
+    if (opt_lcs)
+	errmsg = set_listchars_option(curwin, val,
+		**local_ptr == NUL || !(opt_flags & OPT_GLOBAL));
+    else
+	errmsg = set_fillchars_option(curwin, val,
+		**local_ptr == NUL || !(opt_flags & OPT_GLOBAL));
+    if (errmsg != NULL)
+	return errmsg;
+
+    tabpage_T	*tp;
+    win_T	*wp;
+
+    // If the current window is set to use the global
+    // 'listchars'/'fillchars' value, clear the window-local value.
+    if (!(opt_flags & OPT_GLOBAL))
+	clear_string_option(local_ptr);
+    FOR_ALL_TAB_WINDOWS(tp, wp)
+    {
+	// If the current window has a local value need to apply it
+	// again, it was changed when setting the global value.
+	// If no error was returned above, we don't expect an error
+	// here, so ignore the return value.
+	if (opt_lcs)
+	{
+	    if (*wp->w_p_lcs == NUL)
+		(void)set_listchars_option(wp, wp->w_p_lcs, TRUE);
+	}
+	else
+	{
+	    if (*wp->w_p_fcs == NUL)
+		(void)set_fillchars_option(wp, wp->w_p_fcs, TRUE);
+	}
+    }
+
+    redraw_all_later(UPD_NOT_VALID);
+
+    return NULL;
+}
+
+/*
+ * The 'fillchars' option or the 'listchars' option is changed.
+ */
+    char *
+did_set_chars_option(optset_T *args)
+{
+    char_u **varp = (char_u **)args->os_varp;
+    char *errmsg = NULL;
+
+    if (   varp == &p_lcs		// global 'listchars'
+	|| varp == &p_fcs)		// global 'fillchars'
+	errmsg = did_set_global_listfillchars(*varp, varp == &p_lcs,
+							       args->os_flags);
+    else if (varp == &curwin->w_p_lcs)	// local 'listchars'
+	errmsg = set_listchars_option(curwin, *varp, TRUE);
+    else if (varp == &curwin->w_p_fcs)	// local 'fillchars'
+	errmsg = set_fillchars_option(curwin, *varp, TRUE);
+
+    return errmsg;
+}
+
+/*
+ * The 'cinoptions' option is changed.
+ */
+    char *
+did_set_cinoptions(optset_T *args UNUSED)
+{
+    // TODO: recognize errors
+    parse_cino(curbuf);
+
+    return NULL;
+}
+
+#if defined(FEAT_SYN_HL) || defined(PROTO)
+/*
+ * The 'colorcolumn' option is changed.
+ */
+    char *
+did_set_colorcolumn(optset_T *args UNUSED)
+{
+    return check_colorcolumn(curwin);
+}
+#endif
+
+/*
+ * The 'comments' option is changed.
+ */
+    char *
+did_set_comments(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u	*s;
+    char	*errmsg = NULL;
+
+    for (s = *varp; *s; )
+    {
+	while (*s && *s != ':')
+	{
+	    if (vim_strchr((char_u *)COM_ALL, *s) == NULL
+		    && !VIM_ISDIGIT(*s) && *s != '-')
+	    {
+		errmsg = illegal_char(args->os_errbuf, *s);
+		break;
+	    }
+	    ++s;
+	}
+	if (*s++ == NUL)
+	    errmsg = e_missing_colon;
+	else if (*s == ',' || *s == NUL)
+	    errmsg = e_zero_length_string;
+	if (errmsg != NULL)
+	    break;
+	while (*s && *s != ',')
+	{
+	    if (*s == '\\' && s[1] != NUL)
+		++s;
+	    ++s;
+	}
+	s = skip_to_option_part(s);
+    }
+
+    return errmsg;
+}
+
+#if defined(FEAT_FOLDING) || defined(PROTO)
+/*
+ * The 'commentstring' option is changed.
+ */
+    char *
+did_set_commentstring(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (**varp != NUL && strstr((char *)*varp, "%s") == NULL)
+	return e_commentstring_must_be_empty_or_contain_str;
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'complete' option is changed.
+ */
+    char *
+did_set_complete(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u	*s;
+
+    // check if it is a valid value for 'complete' -- Acevedo
+    for (s = *varp; *s;)
+    {
+	while (*s == ',' || *s == ' ')
+	    s++;
+	if (!*s)
+	    break;
+	if (vim_strchr((char_u *)".wbuksid]tU", *s) == NULL)
+	    return illegal_char(args->os_errbuf, *s);
+	if (*++s != NUL && *s != ',' && *s != ' ')
+	{
+	    if (s[-1] == 'k' || s[-1] == 's')
+	    {
+		// skip optional filename after 'k' and 's'
+		while (*s && *s != ',' && *s != ' ')
+		{
+		    if (*s == '\\' && s[1] != NUL)
+			++s;
+		    ++s;
+		}
+	    }
+	    else
+	    {
+		if (args->os_errbuf != NULL)
+		{
+		    sprintf((char *)args->os_errbuf,
+			    _(e_illegal_character_after_chr), *--s);
+		    return args->os_errbuf;
+		}
+		return "";
+	    }
+	}
+    }
+
+    return NULL;
+}
+
+/*
+ * The 'completeopt' option is changed.
+ */
+    char *
+did_set_completeopt(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_cot, p_cot_values, TRUE) != OK)
+	return e_invalid_argument;
+
+    completeopt_was_set();
+    return NULL;
+}
+
+#if (defined(FEAT_PROP_POPUP) && defined(FEAT_QUICKFIX)) || defined(PROTO)
+/*
+ * The 'completepopup' option is changed.
+ */
+    char *
+did_set_completepopup(optset_T *args UNUSED)
+{
+    if (parse_completepopup(NULL) == FAIL)
+	return e_invalid_argument;
+
+    popup_close_info();
+    return NULL;
+}
+#endif
+
+#if defined(BACKSLASH_IN_FILENAME) || defined(PROTO)
+/*
+ * The 'completeslash' option is changed.
+ */
+    char *
+did_set_completeslash(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_csl, p_csl_values, FALSE) != OK
+	    || check_opt_strings(curbuf->b_p_csl, p_csl_values, FALSE) != OK)
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_CONCEAL) || defined(PROTO)
+/*
+ * The 'concealcursor' option is changed.
+ */
+    char *
+did_set_concealcursor(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    return did_set_option_listflag(*varp, (char_u *)COCU_ALL, args->os_errbuf);
+}
+#endif
+
+/*
+ * The 'cpoptions' option is changed.
+ */
+    char *
+did_set_cpoptions(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    return did_set_option_listflag(*varp, (char_u *)CPO_ALL, args->os_errbuf);
+}
+
+#if defined(FEAT_CRYPT) || defined(PROTO)
+/*
+ * The 'cryptkey' option is changed.
+ */
+    char *
+did_set_cryptkey(optset_T *args)
+{
+    // Make sure the ":set" command doesn't show the new value in the
+    // history.
+    remove_key_from_history();
+
+    if (STRCMP(curbuf->b_p_key, args->os_oldval.string) != 0)
+    {
+	// Need to update the swapfile.
+	ml_set_crypt_key(curbuf, args->os_oldval.string,
+		*curbuf->b_p_cm == NUL ? p_cm : curbuf->b_p_cm);
+	changed_internal();
+    }
+
+    return NULL;
+}
+
+/*
+ * The 'cryptmethod' option is changed.
+ */
+    char *
+did_set_cryptmethod(optset_T *args)
+{
+    char_u  *p;
+    char_u  *s;
+
+    if (args->os_flags & OPT_LOCAL)
+	p = curbuf->b_p_cm;
+    else
+	p = p_cm;
+    if (check_opt_strings(p, p_cm_values, TRUE) != OK)
+	return e_invalid_argument;
+    else if (crypt_self_test() == FAIL)
+	return e_invalid_argument;
+
+    // When setting the global value to empty, make it "zip".
+    if (*p_cm == NUL)
+    {
+	free_string_option(p_cm);
+	p_cm = vim_strsave((char_u *)"zip");
+    }
+    // When using ":set cm=name" the local value is going to be empty.
+    // Do that here, otherwise the crypt functions will still use the
+    // local value.
+    if ((args->os_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0)
+    {
+	free_string_option(curbuf->b_p_cm);
+	curbuf->b_p_cm = empty_option;
+    }
+
+    // Need to update the swapfile when the effective method changed.
+    // Set "s" to the effective old value, "p" to the effective new
+    // method and compare.
+    if ((args->os_flags & OPT_LOCAL) && *args->os_oldval.string == NUL)
+	s = p_cm;  // was previously using the global value
+    else
+	s = args->os_oldval.string;
+    if (*curbuf->b_p_cm == NUL)
+	p = p_cm;  // is now using the global value
+    else
+	p = curbuf->b_p_cm;
+    if (STRCMP(s, p) != 0)
+	ml_set_crypt_key(curbuf, curbuf->b_p_key, s);
+
+    // If the global value changes need to update the swapfile for all
+    // buffers using that value.
+    if ((args->os_flags & OPT_GLOBAL)
+	    && STRCMP(p_cm, args->os_oldval.string) != 0)
+    {
+	buf_T	*buf;
+
+	FOR_ALL_BUFFERS(buf)
+	    if (buf != curbuf && *buf->b_p_cm == NUL)
+		ml_set_crypt_key(buf, buf->b_p_key, args->os_oldval.string);
+    }
+    return NULL;
+}
+#endif
+
+#if (defined(FEAT_CSCOPE) && defined(FEAT_QUICKFIX)) || defined(PROTO)
+/*
+ * The 'cscopequickfix' option is changed.
+ */
+    char *
+did_set_cscopequickfix(optset_T *args UNUSED)
+{
+    char_u	*p;
+
+    if (p_csqf == NULL)
+	return NULL;
+
+    p = p_csqf;
+    while (*p != NUL)
+    {
+	if (vim_strchr((char_u *)CSQF_CMDS, *p) == NULL
+		|| p[1] == NUL
+		|| vim_strchr((char_u *)CSQF_FLAGS, p[1]) == NULL
+		|| (p[2] != NUL && p[2] != ','))
+	    return e_invalid_argument;
+	else if (p[2] == NUL)
+	    break;
+	else
+	    p += 3;
+    }
+
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_SYN_HL) || defined(PROTO)
+/*
+ * The 'cursorlineopt' option is changed.
+ */
+    char *
+did_set_cursorlineopt(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (**varp == NUL || fill_culopt_flags(*varp, curwin) != OK)
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'debug' option is changed.
+ */
+    char *
+did_set_debug(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_debug, p_debug_values, TRUE);
+}
+
+#if defined(FEAT_DIFF) || defined(PROTO)
+/*
+ * The 'diffopt' option is changed.
+ */
+    char *
+did_set_diffopt(optset_T *args UNUSED)
+{
+    if (diffopt_changed() == FAIL)
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'display' option is changed.
+ */
+    char *
+did_set_display(optset_T *args UNUSED)
+{
+    if (opt_strings_flags(p_dy, p_dy_values, &dy_flags, TRUE) != OK)
+	return e_invalid_argument;
+
+    (void)init_chartab();
+    return NULL;
+}
+
+/*
+ * The 'eadirection' option is changed.
+ */
+    char *
+did_set_eadirection(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_ead, p_ead_values, FALSE);
+}
+
+/*
+ * One of the 'encoding', 'fileencoding', 'termencoding' or 'makeencoding'
+ * options is changed.
+ */
+    char *
+did_set_encoding(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u	**gvarp;
+    char	*errmsg = NULL;
+    char_u	*p;
+
+    // Get the global option to compare with, otherwise we would have to check
+    // two values for all local options.
+    gvarp = (char_u **)get_option_varp_scope(args->os_idx, OPT_GLOBAL);
+
+    if (gvarp == &p_fenc)
+    {
+	if (!curbuf->b_p_ma && args->os_flags != OPT_GLOBAL)
+	    errmsg = e_cannot_make_changes_modifiable_is_off;
+	else if (vim_strchr(*varp, ',') != NULL)
+	    // No comma allowed in 'fileencoding'; catches confusing it
+	    // with 'fileencodings'.
+	    errmsg = e_invalid_argument;
+	else
+	{
+	    // May show a "+" in the title now.
+	    redraw_titles();
+	    // Add 'fileencoding' to the swap file.
+	    ml_setflags(curbuf);
+	}
+    }
+    if (errmsg == NULL)
+    {
+	// canonize the value, so that STRCMP() can be used on it
+	p = enc_canonize(*varp);
+	if (p != NULL)
+	{
+	    vim_free(*varp);
+	    *varp = p;
+	}
+	if (varp == &p_enc)
+	{
+	    errmsg = mb_init();
+	    redraw_titles();
+	}
+    }
+
+#if defined(FEAT_GUI_GTK)
+    if (errmsg == NULL && varp == &p_tenc && gui.in_use)
+    {
+	// GTK uses only a single encoding, and that is UTF-8.
+	if (STRCMP(p_tenc, "utf-8") != 0)
+	    errmsg = e_cannot_be_changed_in_gtk_GUI;
+    }
+#endif
+
+    if (errmsg == NULL)
+    {
+#ifdef FEAT_KEYMAP
+	// When 'keymap' is used and 'encoding' changes, reload the keymap
+	// (with another encoding).
+	if (varp == &p_enc && *curbuf->b_p_keymap != NUL)
+	    (void)keymap_init();
+#endif
+
+	// When 'termencoding' is not empty and 'encoding' changes or when
+	// 'termencoding' changes, need to setup for keyboard input and
+	// display output conversion.
+	if (((varp == &p_enc && *p_tenc != NUL) || varp == &p_tenc))
+	{
+	    if (convert_setup(&input_conv, p_tenc, p_enc) == FAIL
+		    || convert_setup(&output_conv, p_enc, p_tenc) == FAIL)
+	    {
+		semsg(_(e_cannot_convert_between_str_and_str),
+			p_tenc, p_enc);
+		errmsg = e_invalid_argument;
+	    }
+	}
+
+#if defined(MSWIN)
+	// $HOME, $VIM and $VIMRUNTIME may have characters in active code page.
+	if (varp == &p_enc)
+	{
+	    init_homedir();
+	    init_vimdir();
+	}
+#endif
+    }
+
+    return errmsg;
+}
+
+/*
+ * The 'eventignore' option is changed.
+ */
+    char *
+did_set_eventignore(optset_T *args UNUSED)
+{
+    if (check_ei() == FAIL)
+	return e_invalid_argument;
+    return NULL;
+}
+
+/*
+ * The 'fileformat' option is changed.
+ */
+    char *
+did_set_fileformat(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (!curbuf->b_p_ma && !(args->os_flags & OPT_GLOBAL))
+	return e_cannot_make_changes_modifiable_is_off;
+    else if (check_opt_strings(*varp, p_ff_values, FALSE) != OK)
+	return e_invalid_argument;
+
+    // may also change 'textmode'
+    if (get_fileformat(curbuf) == EOL_DOS)
+	curbuf->b_p_tx = TRUE;
+    else
+	curbuf->b_p_tx = FALSE;
+    redraw_titles();
+    // update flag in swap file
+    ml_setflags(curbuf);
+    // Redraw needed when switching to/from "mac": a CR in the text
+    // will be displayed differently.
+    if (get_fileformat(curbuf) == EOL_MAC || *args->os_oldval.string == 'm')
+	redraw_curbuf_later(UPD_NOT_VALID);
+
+    return NULL;
+}
+
+/*
+ * The 'fileformats' option is changed.
+ */
+    char *
+did_set_fileformats(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_ffs, p_ff_values, TRUE) != OK)
+	return e_invalid_argument;
+
+    // also change 'textauto'
+    if (*p_ffs == NUL)
+	p_ta = FALSE;
+    else
+	p_ta = TRUE;
+
+    return NULL;
+}
+
+/*
+ * The 'filetype' or the 'syntax' option is changed.
+ */
+    char *
+did_set_filetype_or_syntax(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (!valid_filetype(*varp))
+	return e_invalid_argument;
+
+    args->os_value_changed = STRCMP(args->os_oldval.string, *varp) != 0;
+
+    // Since we check the value, there is no need to set P_INSECURE,
+    // even when the value comes from a modeline.
+    args->os_value_checked = TRUE;
+
+    return NULL;
+}
+
+#if defined(FEAT_FOLDING) || defined(PROTO)
+/*
+ * The 'foldclose' option is changed.
+ */
+    char *
+did_set_foldclose(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_fcl, p_fcl_values, TRUE);
+}
+#endif
+
+#if (defined(FEAT_EVAL) && defined(FEAT_FOLDING)) || defined(PROTO)
+/*
+ * The 'foldexpr' option is changed.
+ */
+    char *
+did_set_foldexpr(optset_T *args)
+{
+    (void)did_set_optexpr(args);
+    if (foldmethodIsExpr(curwin))
+	foldUpdateAll(curwin);
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_FOLDING) || defined(PROTO)
+/*
+ * The 'foldignore' option is changed.
+ */
+    char *
+did_set_foldignore(optset_T *args UNUSED)
+{
+    if (foldmethodIsIndent(curwin))
+	foldUpdateAll(curwin);
+    return NULL;
+}
+
+/*
+ * The 'foldmarker' option is changed.
+ */
+    char *
+did_set_foldmarker(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u	*p;
+
+    p = vim_strchr(*varp, ',');
+    if (p == NULL)
+	return e_comma_required;
+    else if (p == *varp || p[1] == NUL)
+	return e_invalid_argument;
+    else if (foldmethodIsMarker(curwin))
+	foldUpdateAll(curwin);
+
+    return NULL;
+}
+
+/*
+ * The 'foldmethod' option is changed.
+ */
+    char *
+did_set_foldmethod(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (check_opt_strings(*varp, p_fdm_values, FALSE) != OK
+	    || *curwin->w_p_fdm == NUL)
+	return e_invalid_argument;
+
+    foldUpdateAll(curwin);
+    if (foldmethodIsDiff(curwin))
+	newFoldLevel();
+    return NULL;
+}
+
+/*
+ * The 'foldopen' option is changed.
+ */
+    char *
+did_set_foldopen(optset_T *args UNUSED)
+{
+    return did_set_opt_flags(p_fdo, p_fdo_values, &fdo_flags, TRUE);
+}
+#endif
+
+/*
+ * The 'formatoptions' option is changed.
+ */
+    char *
+did_set_formatoptions(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    return did_set_option_listflag(*varp, (char_u *)FO_ALL, args->os_errbuf);
+}
+
+#if defined(CURSOR_SHAPE) || defined(PROTO)
+/*
+ * The 'guicursor' option is changed.
+ */
+    char *
+did_set_guicursor(optset_T *args UNUSED)
+{
+    return parse_shape_opt(SHAPE_CURSOR);
+}
+#endif
+
+#if defined(FEAT_GUI) || defined(PROTO)
+/*
+ * The 'guifont' option is changed.
+ */
+    char *
+did_set_guifont(optset_T *args UNUSED)
+{
+    char_u	*p;
+    char	*errmsg = NULL;
+
+    if (gui.in_use)
+    {
+	p = p_guifont;
+# if defined(FEAT_GUI_GTK)
+	// Put up a font dialog and let the user select a new value.
+	// If this is cancelled go back to the old value but don't
+	// give an error message.
+	if (STRCMP(p, "*") == 0)
+	{
+	    p = gui_mch_font_dialog(args->os_oldval.string);
+	    free_string_option(p_guifont);
+	    p_guifont = (p != NULL) ? p : vim_strsave(args->os_oldval.string);
+	}
+# endif
+	if (p != NULL && gui_init_font(p_guifont, FALSE) != OK)
+	{
+# if defined(FEAT_GUI_MSWIN) || defined(FEAT_GUI_PHOTON)
+	    if (STRCMP(p_guifont, "*") == 0)
+	    {
+		// Dialog was cancelled: Keep the old value without giving
+		// an error message.
+		free_string_option(p_guifont);
+		p_guifont = vim_strsave(args->os_oldval.string);
+	    }
+	    else
+# endif
+		errmsg = e_invalid_fonts;
+	}
+    }
+
+    return errmsg;
+}
+
+# if defined(FEAT_XFONTSET) || defined(PROTO)
+/*
+ * The 'guifontset' option is changed.
+ */
+    char *
+did_set_guifontset(optset_T *args UNUSED)
+{
+    char *errmsg = NULL;
+
+    if (STRCMP(p_guifontset, "*") == 0)
+	errmsg = e_cant_select_fontset;
+    else if (gui.in_use && gui_init_font(p_guifontset, TRUE) != OK)
+	errmsg = e_invalid_fontset;
+
+    return errmsg;
+}
+# endif
+
+/*
+ * The 'guifontwide' option is changed.
+ */
+    char *
+did_set_guifontwide(optset_T *args UNUSED)
+{
+    char *errmsg = NULL;
+
+    if (STRCMP(p_guifontwide, "*") == 0)
+	errmsg = e_cant_select_wide_font;
+    else if (gui_get_wide_font() == FAIL)
+	errmsg = e_invalid_wide_font;
+
+    return errmsg;
+}
+#endif
+
+#if defined(FEAT_GUI_GTK) || defined(PROTO)
+/*
+ * The 'guiligatures' option is changed.
+ */
+    char *
+did_set_guiligatures(optset_T *args UNUSED)
+{
+    gui_set_ligatures();
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_GUI) || defined(PROTO)
+/*
+ * The 'guioptions' option is changed.
+ */
+    char *
+did_set_guioptions(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char *errmsg;
+
+    errmsg = did_set_option_listflag(*varp, (char_u *)GO_ALL, args->os_errbuf);
+    if (errmsg != NULL)
+	return errmsg;
+
+    gui_init_which_components(args->os_oldval.string);
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_GUI_TABLINE) || defined(PROTO)
+/*
+ * The 'guitablabel' option is changed.
+ */
+    char *
+did_set_guitablabel(optset_T *args UNUSED)
+{
+    redraw_tabline = TRUE;
+    return NULL;
+}
+#endif
+
+/*
+ * The 'helpfile' option is changed.
+ */
+    char *
+did_set_helpfile(optset_T *args UNUSED)
+{
+    // May compute new values for $VIM and $VIMRUNTIME
+    if (didset_vim)
+	vim_unsetenv_ext((char_u *)"VIM");
+    if (didset_vimruntime)
+	vim_unsetenv_ext((char_u *)"VIMRUNTIME");
+    return NULL;
+}
+
+#if defined(FEAT_MULTI_LANG) || defined(PROTO)
+/*
+ * The 'helplang' option is changed.
+ */
+    char *
+did_set_helplang(optset_T *args UNUSED)
+{
+    char *errmsg = NULL;
+
+    // Check for "", "ab", "ab,cd", etc.
+    for (char_u *s = p_hlg; *s != NUL; s += 3)
+    {
+	if (s[1] == NUL || ((s[2] != ',' || s[3] == NUL) && s[2] != NUL))
+	{
+	    errmsg = e_invalid_argument;
+	    break;
+	}
+	if (s[2] == NUL)
+	    break;
+    }
+
+    return errmsg;
+}
+#endif
+
+/*
+ * The 'highlight' option is changed.
+ */
+    char *
+did_set_highlight(optset_T *args UNUSED)
+{
+    if (highlight_changed() == FAIL)
+	return e_invalid_argument;	// invalid flags
+
+    return NULL;
+}
+
+/*
+ * The 'titlestring' or the 'iconstring' option is changed.
+ */
+    static char *
+parse_titleiconstring(optset_T *args UNUSED, int flagval UNUSED)
+{
+#ifdef FEAT_STL_OPT
+    char_u	**varp = (char_u **)args->os_varp;
+
+    // NULL => statusline syntax
+    if (vim_strchr(*varp, '%') && check_stl_option(*varp) == NULL)
+	stl_syntax |= flagval;
+    else
+	stl_syntax &= ~flagval;
+#endif
+    did_set_title();
+
+    return NULL;
+}
+
+/*
+ * The 'iconstring' option is changed.
+ */
+    char *
+did_set_iconstring(optset_T *args)
+{
+    int flagval = 0;
+
+#ifdef FEAT_STL_OPT
+    flagval = STL_IN_ICON;
+#endif
+
+    return parse_titleiconstring(args, flagval);
+}
+
+#if (defined(FEAT_XIM) && defined(FEAT_GUI_GTK)) || defined(PROTO)
+/*
+ * The 'imactivatekey' option is changed.
+ */
+    char *
+did_set_imactivatekey(optset_T *args UNUSED)
+{
+    if (!im_xim_isvalid_imactivate())
+	return e_invalid_argument;
+    return NULL;
+}
+#endif
+
+/*
+ * The 'isident' or the 'iskeyword' or the 'isprint' or the 'isfname' option is
+ * changed.
+ */
+    char *
+did_set_isopt(optset_T *args)
+{
+    // 'isident', 'iskeyword', 'isprint or 'isfname' option: refill g_chartab[]
+    // If the new option is invalid, use old value.
+    // 'lisp' option: refill g_chartab[] for '-' char.
+    if (init_chartab() == FAIL)
+    {
+	args->os_restore_chartab = TRUE;// need to restore the chartab.
+	return e_invalid_argument;	// error in value
+    }
+
+    return NULL;
+}
+
+#if defined(FEAT_KEYMAP) || defined(PROTO)
+/*
+ * The 'keymap' option is changed.
+ */
+    char *
+did_set_keymap(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char *errmsg = NULL;
+
+    if (!valid_filetype(*varp))
+	errmsg = e_invalid_argument;
+    else
+    {
+	int	    secure_save = secure;
+
+	// Reset the secure flag, since the value of 'keymap' has
+	// been checked to be safe.
+	secure = 0;
+
+	// load or unload key mapping tables
+	errmsg = keymap_init();
+
+	secure = secure_save;
+
+	// Since we check the value, there is no need to set P_INSECURE,
+	// even when the value comes from a modeline.
+	args->os_value_checked = TRUE;
+    }
+
+    if (errmsg == NULL)
+    {
+	if (*curbuf->b_p_keymap != NUL)
+	{
+	    // Installed a new keymap, switch on using it.
+	    curbuf->b_p_iminsert = B_IMODE_LMAP;
+	    if (curbuf->b_p_imsearch != B_IMODE_USE_INSERT)
+		curbuf->b_p_imsearch = B_IMODE_LMAP;
+	}
+	else
+	{
+	    // Cleared the keymap, may reset 'iminsert' and 'imsearch'.
+	    if (curbuf->b_p_iminsert == B_IMODE_LMAP)
+		curbuf->b_p_iminsert = B_IMODE_NONE;
+	    if (curbuf->b_p_imsearch == B_IMODE_LMAP)
+		curbuf->b_p_imsearch = B_IMODE_USE_INSERT;
+	}
+	if ((args->os_flags & OPT_LOCAL) == 0)
+	{
+	    set_iminsert_global();
+	    set_imsearch_global();
+	}
+	status_redraw_curbuf();
+    }
+
+    return errmsg;
+}
+#endif
+
+/*
+ * The 'keymodel' option is changed.
+ */
+    char *
+did_set_keymodel(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_km, p_km_values, TRUE) != OK)
+	return e_invalid_argument;
+
+    km_stopsel = (vim_strchr(p_km, 'o') != NULL);
+    km_startsel = (vim_strchr(p_km, 'a') != NULL);
+    return NULL;
+}
+
+/*
+ * The 'keyprotocol' option is changed.
+ */
+    char *
+did_set_keyprotocol(optset_T *args UNUSED)
+{
+    if (match_keyprotocol(NULL) == KEYPROTOCOL_FAIL)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * The 'lispoptions' option is changed.
+ */
+    char *
+did_set_lispoptions(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (**varp != NUL
+	    && STRCMP(*varp, "expr:0") != 0
+	    && STRCMP(*varp, "expr:1") != 0)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * The 'matchpairs' option is changed.
+ */
+    char *
+did_set_matchpairs(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u	*p;
+
+    if (has_mbyte)
+    {
+	for (p = *varp; *p != NUL; ++p)
+	{
+	    int x2 = -1;
+	    int x3 = -1;
+
+	    p += mb_ptr2len(p);
+	    if (*p != NUL)
+		x2 = *p++;
+	    if (*p != NUL)
+	    {
+		x3 = mb_ptr2char(p);
+		p += mb_ptr2len(p);
+	    }
+	    if (x2 != ':' || x3 == -1 || (*p != NUL && *p != ','))
+		return e_invalid_argument;
+	    if (*p == NUL)
+		break;
+	}
+    }
+    else
+    {
+	// Check for "x:y,x:y"
+	for (p = *varp; *p != NUL; p += 4)
+	{
+	    if (p[1] != ':' || p[2] == NUL || (p[3] != NUL && p[3] != ','))
+		return e_invalid_argument;
+	    if (p[3] == NUL)
+		break;
+	}
+    }
+
+    return NULL;
+}
+
+#if defined(FEAT_SPELL) || defined(PROTO)
+/*
+ * The 'mkspellmem' option is changed.
+ */
+    char *
+did_set_mkspellmem(optset_T *args UNUSED)
+{
+    if (spell_check_msm() != OK)
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'mouse' option is changed.
+ */
+    char *
+did_set_mouse(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    return did_set_option_listflag(*varp, (char_u *)MOUSE_ALL,
+							args->os_errbuf);
+}
+
+/*
+ * The 'mousemodel' option is changed.
+ */
+    char *
+did_set_mousemodel(optset_T *args UNUSED)
+{
+    if (check_opt_strings(p_mousem, p_mousem_values, FALSE) != OK)
+	return e_invalid_argument;
+#if defined(FEAT_GUI_MOTIF) && defined(FEAT_MENU) && (XmVersion <= 1002)
+    else if (*p_mousem != *oldval)
+	// Changed from "extend" to "popup" or "popup_setpos" or vv: need
+	// to create or delete the popup menus.
+	gui_motif_update_mousemodel(root_menu);
+#endif
+
+    return NULL;
+}
+
+#if defined(FEAT_MOUSESHAPE) || defined(PROTO)
+    char *
+did_set_mouseshape(optset_T *args UNUSED)
+{
+    char *errmsg = NULL;
+
+    errmsg = parse_shape_opt(SHAPE_MOUSE);
+    update_mouseshape(-1);
+
+    return errmsg;
+}
+#endif
+
+/*
+ * The 'nrformats' option is changed.
+ */
+    char *
+did_set_nrformats(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    return did_set_opt_strings(*varp, p_nf_values, TRUE);
+}
+
+#if defined(FEAT_EVAL) || defined(PROTO)
+/*
+ * One of the '*expr' options is changed: 'balloonexpr', 'diffexpr',
+ * 'foldexpr', 'foldtext', 'formatexpr', 'includeexpr', 'indentexpr',
+ * 'patchexpr', 'printexpr' and 'charconvert'.
+ *
+ */
+    char *
+did_set_optexpr(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    // If the option value starts with <SID> or s:, then replace that with
+    // the script identifier.
+    char_u *name = get_scriptlocal_funcname(*varp);
+    if (name != NULL)
+    {
+	free_string_option(*varp);
+	*varp = name;
+    }
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'pastetoggle' option is changed.
+ */
+    char *
+did_set_pastetoggle(optset_T *args UNUSED)
+{
+    char_u	*p;
+
+    // translate key codes like in a mapping
+    if (*p_pt)
+    {
+	(void)replace_termcodes(p_pt, &p,
+		REPTERM_FROM_PART | REPTERM_DO_LT, NULL);
+	if (p != NULL)
+	{
+	    free_string_option(p_pt);
+	    p_pt = p;
+	}
+    }
+
+    return NULL;
+}
+
+#if defined(FEAT_PROP_POPUP) || defined(PROTO)
+/*
+ * The 'previewpopup' option is changed.
+ */
+    char *
+did_set_previewpopup(optset_T *args UNUSED)
+{
+    if (parse_previewpopup(NULL) == FAIL)
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_POSTSCRIPT) || defined(PROTO)
+/*
+ * The 'printencoding' option is changed.
+ */
+    char *
+did_set_printencoding(optset_T *args UNUSED)
+{
+    char_u	*s, *p;
+
+    // Canonize 'printencoding' if VIM standard one
+    p = enc_canonize(p_penc);
+    if (p != NULL)
+    {
+	vim_free(p_penc);
+	p_penc = p;
+    }
+    else
+    {
+	// Ensure lower case and '-' for '_'
+	for (s = p_penc; *s != NUL; s++)
+	{
+	    if (*s == '_')
+		*s = '-';
+	    else
+		*s = TOLOWER_ASC(*s);
+	}
+    }
+
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_STL_OPT) || defined(PROTO)
+/*
+ * The 'statusline' or the 'tabline' or the 'rulerformat' option is changed.
+ * "rulerformat" is TRUE if the 'rulerformat' option is changed.
+ */
+    static char *
+parse_statustabline_rulerformat(optset_T *args, int rulerformat)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u	*s;
+    char	*errmsg = NULL;
+    int		wid;
+
+    if (rulerformat)	// reset ru_wid first
+	ru_wid = 0;
+    s = *varp;
+    if (rulerformat && *s == '%')
+    {
+	// set ru_wid if 'ruf' starts with "%99("
+	if (*++s == '-')	// ignore a '-'
+	    s++;
+	wid = getdigits(&s);
+	if (wid && *s == '(' && (errmsg = check_stl_option(p_ruf)) == NULL)
+	    ru_wid = wid;
+	else
+	    errmsg = check_stl_option(p_ruf);
+    }
+    // check 'statusline' or 'tabline' only if it doesn't start with "%!"
+    else if (rulerformat || s[0] != '%' || s[1] != '!')
+	errmsg = check_stl_option(s);
+    if (rulerformat && errmsg == NULL)
+	comp_col();
+
+    return errmsg;
+}
+#endif
+
+#if defined(FEAT_RENDER_OPTIONS) || defined(PROTO)
+/*
+ * The 'renderoptions' option is changed.
+ */
+    char *
+did_set_renderoptions(optset_T *args UNUSED)
+{
+    if (!gui_mch_set_rendering_options(p_rop))
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_RIGHTLEFT) || defined(PROTO)
+/*
+ * The 'rightleftcmd' option is changed.
+ */
+    char *
+did_set_rightleftcmd(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    // Currently only "search" is a supported value.
+    if (**varp != NUL && STRCMP(*varp, "search") != 0)
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_STL_OPT) || defined(PROTO)
+/*
+ * The 'rulerformat' option is changed.
+ */
+    char *
+did_set_rulerformat(optset_T *args)
+{
+    return parse_statustabline_rulerformat(args, TRUE);
+}
+#endif
+
+/*
+ * The 'scrollopt' option is changed.
+ */
+    char *
+did_set_scrollopt(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_sbo, p_scbopt_values, TRUE);
+}
+
+/*
+ * The 'selection' option is changed.
+ */
+    char *
+did_set_selection(optset_T *args UNUSED)
+{
+    if (*p_sel == NUL || check_opt_strings(p_sel, p_sel_values, FALSE) != OK)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * The 'selectmode' option is changed.
+ */
+    char *
+did_set_selectmode(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_slm, p_slm_values, TRUE);
+}
+
+#if defined(FEAT_SESSION) || defined(PROTO)
+/*
+ * The 'sessionoptions' option is changed.
+ */
+    char *
+did_set_sessionoptions(optset_T *args)
+{
+    if (opt_strings_flags(p_ssop, p_ssop_values, &ssop_flags, TRUE) != OK)
+	return e_invalid_argument;
+    if ((ssop_flags & SSOP_CURDIR) && (ssop_flags & SSOP_SESDIR))
+    {
+	// Don't allow both "sesdir" and "curdir".
+	(void)opt_strings_flags(args->os_oldval.string, p_ssop_values,
+							&ssop_flags, TRUE);
+	return e_invalid_argument;
+    }
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'shortmess' option is changed.
+ */
+    char *
+did_set_shortmess(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    return did_set_option_listflag(*varp, (char_u *)SHM_ALL, args->os_errbuf);
+}
+
+#if defined(FEAT_LINEBREAK) || defined(PROTO)
+/*
+ * The 'showbreak' option is changed.
+ */
+    char *
+did_set_showbreak(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u	*s;
+
+    for (s = *varp; *s; )
+    {
+	if (ptr2cells(s) != 1)
+	    return e_showbreak_contains_unprintable_or_wide_character;
+	MB_PTR_ADV(s);
+    }
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'showcmdloc' option is changed.
+ */
+    char *
+did_set_showcmdloc(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_sloc, p_sloc_values, FALSE);
+}
+
+#if defined(FEAT_SIGNS) || defined(PROTO)
+/*
+ * The 'signcolumn' option is changed.
+ */
+    char *
+did_set_signcolumn(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (check_opt_strings(*varp, p_scl_values, FALSE) != OK)
+	return e_invalid_argument;
+    // When changing the 'signcolumn' to or from 'number', recompute the
+    // width of the number column if 'number' or 'relativenumber' is set.
+    if (((*args->os_oldval.string == 'n' && args->os_oldval.string[1] == 'u')
+		|| (*curwin->w_p_scl == 'n' && *(curwin->w_p_scl + 1) =='u'))
+	    && (curwin->w_p_nu || curwin->w_p_rnu))
+	curwin->w_nrwidth_line_count = 0;
+
+    return NULL;
+}
+#endif
+
+#if defined(FEAT_SPELL) || defined(PROTO)
+/*
+ * The 'spellcapcheck' option is changed.
+ */
+    char *
+did_set_spellcapcheck(optset_T *args UNUSED)
+{
+    // compile the regexp program.
+    return compile_cap_prog(curwin->w_s);
+}
+
+/*
+ * The 'spellfile' option is changed.
+ */
+    char *
+did_set_spellfile(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (!valid_spellfile(*varp))
+	return e_invalid_argument;
+
+    // If there is a window for this buffer in which 'spell' is set load the
+    // wordlists.
+    return did_set_spell_option(TRUE);
+}
+
+/*
+ * The 'spell' option is changed.
+ */
+    char *
+did_set_spelllang(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (!valid_spelllang(*varp))
+	return e_invalid_argument;
+
+    // If there is a window for this buffer in which 'spell' is set load the
+    // wordlists.
+    return did_set_spell_option(FALSE);
+}
+
+/*
+ * The 'spelloptions' option is changed.
+ */
+    char *
+did_set_spelloptions(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (**varp != NUL && STRCMP(*varp, "camel") != 0)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * The 'spellsuggest' option is changed.
+ */
+    char *
+did_set_spellsuggest(optset_T *args UNUSED)
+{
+    if (spell_check_sps() != OK)
+	return e_invalid_argument;
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'splitkeep' option is changed.
+ */
+    char *
+did_set_splitkeep(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_spk, p_spk_values, FALSE);
+}
+
+#if defined(FEAT_STL_OPT) || defined(PROTO)
+/*
+ * The 'statusline' option is changed.
+ */
+    char *
+did_set_statusline(optset_T *args)
+{
+    return parse_statustabline_rulerformat(args, FALSE);
+}
+#endif
+
+/*
+ * The 'swapsync' option is changed.
+ */
+    char *
+did_set_swapsync(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_sws, p_sws_values, FALSE);
+}
+
+/*
+ * The 'switchbuf' option is changed.
+ */
+    char *
+did_set_switchbuf(optset_T *args UNUSED)
+{
+    return did_set_opt_flags(p_swb, p_swb_values, &swb_flags, TRUE);
+}
+
+#if defined(FEAT_STL_OPT) || defined(PROTO)
+/*
+ * The 'tabline' option is changed.
+ */
+    char *
+did_set_tabline(optset_T *args)
+{
+    return parse_statustabline_rulerformat(args, FALSE);
+}
+#endif
+
+/*
+ * The 'tagcase' option is changed.
+ */
+    char *
+did_set_tagcase(optset_T *args)
+{
+    unsigned int	*flags;
+    char_u		*p;
+
+    if (args->os_flags & OPT_LOCAL)
+    {
+	p = curbuf->b_p_tc;
+	flags = &curbuf->b_tc_flags;
+    }
+    else
+    {
+	p = p_tc;
+	flags = &tc_flags;
+    }
+
+    if ((args->os_flags & OPT_LOCAL) && *p == NUL)
+	// make the local value empty: use the global value
+	*flags = 0;
+    else if (*p == NUL
+	    || opt_strings_flags(p, p_tc_values, flags, FALSE) != OK)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * The 'term' option is changed.
+ */
+    char *
+did_set_term(optset_T *args UNUSED)
+{
+    if (T_NAME[0] == NUL)
+	return e_cannot_set_term_to_empty_string;
+#ifdef FEAT_GUI
+    if (gui.in_use)
+	return e_cannot_change_term_in_GUI;
+    if (term_is_gui(T_NAME))
+	return e_use_gui_to_start_GUI;
+#endif
+    if (set_termname(T_NAME) == FAIL)
+	return e_not_found_in_termcap;
+
+    // Screen colors may have changed.
+    redraw_later_clear();
+
+    return NULL;
+}
+
+/*
+ * Some terminal option (t_xxx) is changed
+ */
+    char *
+did_set_term_option(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if (!full_screen)
+	return NULL;
+
+    // ":set t_Co=0" and ":set t_Co=1" do ":set t_Co="
+    if (varp == &T_CCO)
+    {
+	int colors = atoi((char *)T_CCO);
+
+	// Only reinitialize colors if t_Co value has really changed to
+	// avoid expensive reload of colorscheme if t_Co is set to the
+	// same value multiple times.
+	if (colors != t_colors)
+	{
+	    t_colors = colors;
+	    if (t_colors <= 1)
+	    {
+		vim_free(T_CCO);
+		T_CCO = empty_option;
+	    }
+#if defined(FEAT_VTP) && defined(FEAT_TERMGUICOLORS)
+	    if (is_term_win32())
+	    {
+		swap_tcap();
+		args->os_did_swaptcap = TRUE;
+	    }
+#endif
+	    // We now have a different color setup, initialize it again.
+	    init_highlight(TRUE, FALSE);
+	}
+    }
+    ttest(FALSE);
+    if (varp == &T_ME)
+    {
+	out_str(T_ME);
+	redraw_later(UPD_CLEAR);
+#if defined(MSWIN) && (!defined(FEAT_GUI_MSWIN) || defined(VIMDLL))
+	// Since t_me has been set, this probably means that the user
+	// wants to use this as default colors.  Need to reset default
+	// background/foreground colors.
+# ifdef VIMDLL
+	if (!gui.in_use && !gui.starting)
+# endif
+	    mch_set_normal_colors();
+#endif
+    }
+    if (varp == &T_BE && termcap_active)
+    {
+	MAY_WANT_TO_LOG_THIS;
+
+	if (*T_BE == NUL)
+	    // When clearing t_BE we assume the user no longer wants
+	    // bracketed paste, thus disable it by writing t_BD.
+	    out_str(T_BD);
+	else
+	    out_str(T_BE);
+    }
+
+    return NULL;
+}
+
+#if defined(FEAT_TERMINAL) || defined(PROTO)
+/*
+ * The 'termwinkey' option is changed.
+ */
+    char *
+did_set_termwinkey(optset_T *args UNUSED)
+{
+    if (*curwin->w_p_twk != NUL && string_to_key(curwin->w_p_twk, TRUE) == 0)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+/*
+ * The 'termwinsize' option is changed.
+ */
+    char *
+did_set_termwinsize(optset_T *args UNUSED)
+{
+    char_u	*p;
+
+    if (*curwin->w_p_tws == NUL)
+	return NULL;
+
+    p = skipdigits(curwin->w_p_tws);
+    if (p == curwin->w_p_tws
+	    || (*p != 'x' && *p != '*')
+	    || *skipdigits(p + 1) != NUL)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+# if defined(MSWIN) || defined(PROTO)
+/*
+ * The 'termwintype' option is changed.
+ */
+    char *
+did_set_termwintype(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_twt, p_twt_values, FALSE);
+}
+# endif
+#endif
+
+/*
+ * The 'titlestring' option is changed.
+ */
+    char *
+did_set_titlestring(optset_T *args)
+{
+    int flagval = 0;
+
+#ifdef FEAT_STL_OPT
+    flagval = STL_IN_TITLE;
+#endif
+    return parse_titleiconstring(args, flagval);
+}
+
+#if (defined(FEAT_TOOLBAR) && !defined(FEAT_GUI_MSWIN)) || defined(PROTO)
+/*
+ * The 'toolbar' option is changed.
+ */
+    char *
+did_set_toolbar(optset_T *args UNUSED)
+{
+    if (opt_strings_flags(p_toolbar, p_toolbar_values, &toolbar_flags,
+								TRUE) != OK)
+	return e_invalid_argument;
+
+    out_flush();
+    gui_mch_show_toolbar((toolbar_flags &
+		(TOOLBAR_TEXT | TOOLBAR_ICONS)) != 0);
+    return NULL;
+}
+#endif
+
+#if (defined(FEAT_TOOLBAR) && defined(FEAT_GUI_GTK)) || defined(PROTO)
+/*
+ * The 'toolbariconsize' option is changed.  GTK+ 2 only.
+ */
+    char *
+did_set_toolbariconsize(optset_T *args UNUSED)
+{
+    if (opt_strings_flags(p_tbis, p_tbis_values, &tbis_flags, FALSE) != OK)
+	return e_invalid_argument;
+
+    out_flush();
+    gui_mch_show_toolbar((toolbar_flags &
+		(TOOLBAR_TEXT | TOOLBAR_ICONS)) != 0);
+    return NULL;
+}
+#endif
+
+#if defined(UNIX) || defined(VMS) || defined(PROTO)
+/*
+ * The 'ttymouse' option is changed.
+ */
+    char *
+did_set_ttymouse(optset_T *args UNUSED)
+{
+    char *errmsg = NULL;
+
+    // Switch the mouse off before changing the escape sequences used for
+    // that.
+    mch_setmouse(FALSE);
+    if (opt_strings_flags(p_ttym, p_ttym_values, &ttym_flags, FALSE) != OK)
+	errmsg = e_invalid_argument;
+    else
+	check_mouse_termcode();
+    if (termcap_active)
+	setmouse();		// may switch it on again
+
+    return errmsg;
+}
+#endif
+
+#if defined(FEAT_VARTABS) || defined(PROTO)
+/*
+ * The 'varsofttabstop' option is changed.
+ */
+    char *
+did_set_varsofttabstop(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u *cp;
+
+    if (!((*varp)[0]) || ((*varp)[0] == '0' && !((*varp)[1])))
+	VIM_CLEAR(curbuf->b_p_vsts_array);
+    else
+    {
+	for (cp = *varp; *cp; ++cp)
+	{
+	    if (vim_isdigit(*cp))
+		continue;
+	    if (*cp == ',' && cp > *varp && *(cp-1) != ',')
+		continue;
+	    return e_invalid_argument;
+	}
+
+	int *oldarray = curbuf->b_p_vsts_array;
+	if (tabstop_set(*varp, &(curbuf->b_p_vsts_array)) == OK)
+	{
+	    if (oldarray)
+		vim_free(oldarray);
+	}
+	else
+	    return e_invalid_argument;
+    }
+
+    return NULL;
+}
+
+/*
+ * The 'vartabstop' option is changed.
+ */
+    char *
+did_set_vartabstop(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+    char_u *cp;
+
+    if (!((*varp)[0]) || ((*varp)[0] == '0' && !((*varp)[1])))
+	VIM_CLEAR(curbuf->b_p_vts_array);
+    else
+    {
+	for (cp = *varp; *cp; ++cp)
+	{
+	    if (vim_isdigit(*cp))
+		continue;
+	    if (*cp == ',' && cp > *varp && *(cp-1) != ',')
+		continue;
+	    return e_invalid_argument;
+	}
+
+	int *oldarray = curbuf->b_p_vts_array;
+
+	if (tabstop_set(*varp, &(curbuf->b_p_vts_array)) == OK)
+	{
+	    vim_free(oldarray);
+# ifdef FEAT_FOLDING
+	    if (foldmethodIsIndent(curwin))
+		foldUpdateAll(curwin);
+# endif
+	}
+	else
+	    return e_invalid_argument;
+    }
+
+    return NULL;
+}
+#endif
+
+/*
+ * The 'verbosefile' option is changed.
+ */
+    char *
+did_set_verbosefile(optset_T *args UNUSED)
+{
+    verbose_stop();
+    if (*p_vfile != NUL && verbose_open() == FAIL)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+#if defined(FEAT_SESSION) || defined(PROTO)
+/*
+ * The 'viewoptions' option is changed.
+ */
+    char *
+did_set_viewoptions(optset_T *args UNUSED)
+{
+    return did_set_opt_flags(p_vop, p_ssop_values, &vop_flags, TRUE);
+}
+#endif
+
+#if defined(FEAT_VIMINFO) || defined(PROTO)
+/*
+ * The 'viminfo' option is changed.
+ */
+    char *
+did_set_viminfo(optset_T *args)
+{
+    char_u	*s;
+    char	*errmsg = NULL;
+
+    for (s = p_viminfo; *s;)
+    {
+	// Check it's a valid character
+	if (vim_strchr((char_u *)"!\"%'/:<@cfhnrs", *s) == NULL)
+	{
+	    errmsg = illegal_char(args->os_errbuf, *s);
+	    break;
+	}
+	if (*s == 'n')	// name is always last one
+	    break;
+	else if (*s == 'r') // skip until next ','
+	{
+	    while (*++s && *s != ',')
+		;
+	}
+	else if (*s == '%')
+	{
+	    // optional number
+	    while (vim_isdigit(*++s))
+		;
+	}
+	else if (*s == '!' || *s == 'h' || *s == 'c')
+	    ++s;		// no extra chars
+	else		// must have a number
+	{
+	    while (vim_isdigit(*++s))
+		;
+
+	    if (!VIM_ISDIGIT(*(s - 1)))
+	    {
+		if (args->os_errbuf != NULL)
+		{
+		    sprintf(args->os_errbuf,
+			    _(e_missing_number_after_angle_str_angle),
+			    transchar_byte(*(s - 1)));
+		    errmsg = args->os_errbuf;
+		}
+		else
+		    errmsg = "";
+		break;
+	    }
+	}
+	if (*s == ',')
+	    ++s;
+	else if (*s)
+	{
+	    if (args->os_errbuf != NULL)
+		errmsg = e_missing_comma;
+	    else
+		errmsg = "";
+	    break;
+	}
+    }
+    if (*p_viminfo && errmsg == NULL && get_viminfo_parameter('\'') < 0)
+	errmsg = e_must_specify_a_value;
+
+    return errmsg;
+}
+#endif
+
+/*
+ * The 'virtualedit' option is changed.
+ */
+    char *
+did_set_virtualedit(optset_T *args)
+{
+    char_u		*ve = p_ve;
+    unsigned int	*flags = &ve_flags;
+
+    if (args->os_flags & OPT_LOCAL)
+    {
+	ve = curwin->w_p_ve;
+	flags = &curwin->w_ve_flags;
+    }
+
+    if ((args->os_flags & OPT_LOCAL) && *ve == NUL)
+	// make the local value empty: use the global value
+	*flags = 0;
+    else
+    {
+	if (opt_strings_flags(ve, p_ve_values, flags, TRUE) != OK)
+	    return e_invalid_argument;
+	else if (STRCMP(ve, args->os_oldval.string) != 0)
+	{
+	    // Recompute cursor position in case the new 've' setting
+	    // changes something.
+	    validate_virtcol();
+	    coladvance(curwin->w_virtcol);
+	}
+    }
+
+    return NULL;
+}
+
+/*
+ * The 'whichwrap' option is changed.
+ */
+    char *
+did_set_whichwrap(optset_T *args)
+{
+    char_u	**varp = (char_u **)args->os_varp;
+
+    return did_set_option_listflag(*varp, (char_u *)WW_ALL, args->os_errbuf);
+}
+
+/*
+ * The 'wildmode' option is changed.
+ */
+    char *
+did_set_wildmode(optset_T *args UNUSED)
+{
+    if (check_opt_wim() == FAIL)
+	return e_invalid_argument;
+    return NULL;
+}
+
+/*
+ * The 'wildoptions' option is changed.
+ */
+    char *
+did_set_wildoptions(optset_T *args UNUSED)
+{
+    return did_set_opt_strings(p_wop, p_wop_values, TRUE);
+}
+
+#if defined(FEAT_WAK) || defined(PROTO)
+/*
+ * The 'winaltkeys' option is changed.
+ */
+    char *
+did_set_winaltkeys(optset_T *args UNUSED)
+{
+    char *errmsg = NULL;
+
+    if (*p_wak == NUL || check_opt_strings(p_wak, p_wak_values, FALSE) != OK)
+	errmsg = e_invalid_argument;
+# ifdef FEAT_MENU
+#  if defined(FEAT_GUI_MOTIF)
+    else if (gui.in_use)
+	gui_motif_set_mnemonics(p_wak[0] == 'y' || p_wak[0] == 'm');
+#  elif defined(FEAT_GUI_GTK)
+    else if (gui.in_use)
+	gui_gtk_set_mnemonics(p_wak[0] == 'y' || p_wak[0] == 'm');
+#  endif
+# endif
+    return errmsg;
+}
+#endif
+
+/*
+ * The 'wincolor' option is changed.
+ */
+    char *
+did_set_wincolor(optset_T *args UNUSED)
+{
+#ifdef FEAT_TERMINAL
+    term_update_wincolor(curwin);
+#endif
+    return NULL;
+}
+
+#ifdef FEAT_SYN_HL
+/*
+ * When the 'syntax' option is set, load the syntax of that name.
+ */
+    static void
+do_syntax_autocmd(int value_changed)
+{
+    static int syn_recursive = 0;
+
+    ++syn_recursive;
+    // Only pass TRUE for "force" when the value changed or not used
+    // recursively, to avoid endless recurrence.
+    apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn, curbuf->b_fname,
+	    value_changed || syn_recursive == 1, curbuf);
+    curbuf->b_flags |= BF_SYN_SET;
+    --syn_recursive;
+}
+#endif
+
+/*
+ * When the 'filetype' option is set, trigger the FileType autocommand.
+ */
+    static void
+do_filetype_autocmd(char_u **varp, int opt_flags, int value_changed)
+{
+    // Skip this when called from a modeline and the filetype was already set
+    // to this value.
+    if ((opt_flags & OPT_MODELINE) && !value_changed)
+	return;
+
+    static int  ft_recursive = 0;
+    int	    secure_save = secure;
+
+    // Reset the secure flag, since the value of 'filetype' has
+    // been checked to be safe.
+    secure = 0;
+
+    ++ft_recursive;
+    did_filetype = TRUE;
+    // Only pass TRUE for "force" when the value changed or not
+    // used recursively, to avoid endless recurrence.
+    apply_autocmds(EVENT_FILETYPE, curbuf->b_p_ft, curbuf->b_fname,
+	    value_changed || ft_recursive == 1, curbuf);
+    --ft_recursive;
+    // Just in case the old "curbuf" is now invalid.
+    if (varp != &(curbuf->b_p_ft))
+	varp = NULL;
+
+    secure = secure_save;
+}
+
+#ifdef FEAT_SPELL
+/*
+ * When the 'spelllang' option is set, source the spell/LANG.vim file in
+ * 'runtimepath'.
+ */
+    static void
+do_spelllang_source(void)
+{
+    char_u	fname[200];
+    char_u	*p;
+    char_u	*q = curwin->w_s->b_p_spl;
+
+    // Skip the first name if it is "cjk".
+    if (STRNCMP(q, "cjk,", 4) == 0)
+	q += 4;
+
+    // They could set 'spellcapcheck' depending on the language.  Use the first
+    // name in 'spelllang' up to '_region' or '.encoding'.
+    for (p = q; *p != NUL; ++p)
+	if (!ASCII_ISALNUM(*p) && *p != '-')
+	    break;
+    if (p > q)
+    {
+	vim_snprintf((char *)fname, 200, "spell/%.*s.vim",
+		(int)(p - q), q);
+	source_runtime(fname, DIP_ALL);
+    }
+}
+#endif
+
+/*
+ * Handle string options that need some action to perform when changed.
+ * The new value must be allocated.
+ * Returns NULL for success, or an untranslated error message for an error.
+ */
+    char *
+did_set_string_option(
+    int		opt_idx,		// index in options[] table
+    char_u	**varp,			// pointer to the option variable
+    char_u	*oldval,		// previous value of the option
+    char_u	*value,			// new value of the option
+    char	*errbuf,		// buffer for errors, or NULL
+    int		opt_flags,		// OPT_LOCAL and/or OPT_GLOBAL
+    int		*value_checked)		// value was checked to be safe, no
+					// need to set P_INSECURE
+{
+    char	*errmsg = NULL;
+    long_u	free_oldval = (get_option_flags(opt_idx) & P_ALLOCED);
+    opt_did_set_cb_T did_set_cb = get_option_did_set_cb(opt_idx);
+    optset_T	args;
+
+    // 'ttytype' is an alias for 'term'.  Both 'term' and 'ttytype' point to
+    // T_NAME.  If 'term' or 'ttytype' is modified, then use the index for the
+    // 'term' option.  Only set the P_ALLOCED flag on 'term'.
+    if (varp == &T_NAME)
+    {
+	opt_idx = findoption((char_u *)"term");
+	if (opt_idx >= 0)
+	{
+	    free_oldval = (get_option_flags(opt_idx) & P_ALLOCED);
+	    did_set_cb = get_option_did_set_cb(opt_idx);
+	}
+    }
+
+    CLEAR_FIELD(args);
+
+    // Disallow changing some options from secure mode
+    if ((secure
+#ifdef HAVE_SANDBOX
+		|| sandbox != 0
+#endif
+		) && (get_option_flags(opt_idx) & P_SECURE))
+	errmsg = e_not_allowed_here;
+    // Check for a "normal" directory or file name in some options.
+    else if (check_illegal_path_names(opt_idx, varp))
+	errmsg = e_invalid_argument;
+    else if (did_set_cb != NULL)
+    {
+	args.os_varp = (char_u *)varp;
+	args.os_idx = opt_idx;
+	args.os_flags = opt_flags;
+	args.os_oldval.string = oldval;
+	args.os_newval.string = value;
+	args.os_errbuf = errbuf;
+	// Invoke the option specific callback function to validate and apply
+	// the new option value.
+	errmsg = did_set_cb(&args);
+
+	// The 'keymap', 'filetype' and 'syntax' option callback functions
+	// may change the os_value_checked field.
+	*value_checked = args.os_value_checked;
+    }
+
+    // If an error is detected, restore the previous value.
+    if (errmsg != NULL)
+    {
+	free_string_option(*varp);
+	*varp = oldval;
+	// When resetting some values, need to act on it.
+	if (args.os_restore_chartab)
+	    (void)init_chartab();
+	if (varp == &p_hl)
+	    (void)highlight_changed();
+    }
+    else
+    {
+#ifdef FEAT_EVAL
+	// Remember where the option was set.
+	set_option_sctx_idx(opt_idx, opt_flags, current_sctx);
+#endif
+	// Free string options that are in allocated memory.
+	// Use "free_oldval", because recursiveness may change the flags under
+	// our fingers (esp. init_highlight()).
+	if (free_oldval)
+	    free_string_option(oldval);
+	set_option_flag(opt_idx, P_ALLOCED);
+
+	if ((opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0
+		&& is_global_local_option(opt_idx))
+	{
+	    // global option with local value set to use global value; free
+	    // the local value and make it empty
+	    char_u *p = get_option_varp_scope(opt_idx, OPT_LOCAL);
+	    free_string_option(*(char_u **)p);
+	    *(char_u **)p = empty_option;
+	}
+
+	// May set global value for local option.
+	else if (!(opt_flags & OPT_LOCAL) && opt_flags != OPT_GLOBAL)
+	    set_string_option_global(opt_idx, varp);
+
+	// Trigger the autocommand only after setting the flags.
+#ifdef FEAT_SYN_HL
+	if (varp == &(curbuf->b_p_syn))
+	    do_syntax_autocmd(args.os_value_changed);
+#endif
+	else if (varp == &(curbuf->b_p_ft))
+	    do_filetype_autocmd(varp, opt_flags, args.os_value_changed);
+#ifdef FEAT_SPELL
+	if (varp == &(curwin->w_s->b_p_spl))
+	    do_spelllang_source();
+#endif
+    }
+
+    if (varp == &p_mouse)
+    {
+	if (*p_mouse == NUL)
+	    mch_setmouse(FALSE);    // switch mouse off
+	else
+	    setmouse();		    // in case 'mouse' changed
+    }
+
+#if defined(FEAT_LUA) || defined(PROTO)
+    if (varp == &p_rtp)
+	update_package_paths_in_lua();
+#endif
+
+#if defined(FEAT_LINEBREAK)
+    // Changing Formatlistpattern when briopt includes the list setting:
+    // redraw
+    if ((varp == &p_flp || varp == &(curbuf->b_p_flp))
+	    && curwin->w_briopt_list)
+	redraw_all_later(UPD_NOT_VALID);
+#endif
+
+    if (curwin->w_curswant != MAXCOL
+		   && (get_option_flags(opt_idx) & (P_CURSWANT | P_RALL)) != 0)
+	curwin->w_set_curswant = TRUE;
+
+    if ((opt_flags & OPT_NO_REDRAW) == 0)
+    {
+#ifdef FEAT_GUI
+	// set when changing an option that only requires a redraw in the GUI
+	int	redraw_gui_only = FALSE;
+
+	if (varp == &p_go			// 'guioptions'
+		|| varp == &p_guifont		// 'guifont'
+# ifdef FEAT_GUI_TABLINE
+		|| varp == &p_gtl		// 'guitablabel'
+		|| varp == &p_gtt		// 'guitabtooltip'
+# endif
+# ifdef FEAT_XFONTSET
+		|| varp == &p_guifontset	// 'guifontset'
+# endif
+		|| varp == &p_guifontwide	// 'guifontwide'
+# ifdef FEAT_GUI_GTK
+		|| varp == &p_guiligatures	// 'guiligatures'
+# endif
+	    )
+	    redraw_gui_only = TRUE;
+
+	// check redraw when it's not a GUI option or the GUI is active.
+	if (!redraw_gui_only || gui.in_use)
+#endif
+	    check_redraw(get_option_flags(opt_idx));
+    }
+
+#if defined(FEAT_VTP) && defined(FEAT_TERMGUICOLORS)
+    if (args.os_did_swaptcap)
+    {
+	set_termname((char_u *)"win32");
+	init_highlight(TRUE, FALSE);
+    }
+#endif
+
+    return errmsg;
+}
+
+/*
+ * Check an option that can be a range of string values.
+ *
+ * Return OK for correct value, FAIL otherwise.
+ * Empty is always OK.
+ */
+    static int
+check_opt_strings(
+    char_u	*val,
+    char	**values,
+    int		list)	    // when TRUE: accept a list of values
+{
+    return opt_strings_flags(val, values, NULL, list);
+}
+
+/*
+ * Handle an option that can be a range of string values.
+ * Set a flag in "*flagp" for each string present.
+ *
+ * Return OK for correct value, FAIL otherwise.
+ * Empty is always OK.
+ */
+    static int
+opt_strings_flags(
+    char_u	*val,		// new value
+    char	**values,	// array of valid string values
+    unsigned	*flagp,
+    int		list)		// when TRUE: accept a list of values
+{
+    int		i;
+    int		len;
+    unsigned	new_flags = 0;
+
+    while (*val)
+    {
+	for (i = 0; ; ++i)
+	{
+	    if (values[i] == NULL)	// val not found in values[]
+		return FAIL;
+
+	    len = (int)STRLEN(values[i]);
+	    if (STRNCMP(values[i], val, len) == 0
+		    && ((list && val[len] == ',') || val[len] == NUL))
+	    {
+		val += len + (val[len] == ',');
+		new_flags |= (1 << i);
+		break;		// check next item in val list
+	    }
+	}
+    }
+    if (flagp != NULL)
+	*flagp = new_flags;
+
+    return OK;
+}
+
+/*
+ * return OK if "p" is a valid fileformat name, FAIL otherwise.
+ */
+    int
+check_ff_value(char_u *p)
+{
+    return check_opt_strings(p, p_ff_values, FALSE);
+}
+
+/*
+ * Save the actual shortmess Flags and clear them temporarily to avoid that
+ * file messages overwrites any output from the following commands.
+ *
+ * Caller must make sure to first call save_clear_shm_value() and then
+ * restore_shm_value() exactly the same number of times.
+ */
+    void
+save_clear_shm_value(void)
+{
+    if (STRLEN(p_shm) >= SHM_LEN)
+    {
+	iemsg(e_internal_error_shortmess_too_long);
+	return;
+    }
+
+    if (++set_shm_recursive == 1)
+    {
+	STRCPY(shm_buf, p_shm);
+	set_option_value_give_err((char_u *)"shm", 0L, (char_u *)"", 0);
+    }
+}
+
+/*
+ * Restore the shortmess Flags set from the save_clear_shm_value() function.
+ */
+    void
+restore_shm_value(void)
+{
+    if (--set_shm_recursive == 0)
+    {
+	set_option_value_give_err((char_u *)"shm", 0L, shm_buf, 0);
+	vim_memset(shm_buf, 0, SHM_LEN);
+    }
+}