Mercurial > vim
changeset 13716:30f9ebe3e602 v8.0.1730
patch 8.0.1730: no configure check for the used C99 features
commit https://github.com/vim/vim/commit/561f8a5a4612751c2a4ebd6bf918cbc3be867350
Author: Bram Moolenaar <Bram@vim.org>
Date: Tue Apr 17 22:02:45 2018 +0200
patch 8.0.1730: no configure check for the used C99 features
Problem: No configure check for the used C99 features.
Solution: Add a compilation check. Tentatively document C99 features.
| author | Christian Brabandt <cb@256bit.org> |
|---|---|
| date | Tue, 17 Apr 2018 22:15:07 +0200 |
| parents | 9e68fff0070f |
| children | 5ccca18a0dff |
| files | runtime/doc/develop.txt src/auto/configure src/configure.ac src/version.c |
| diffstat | 4 files changed, 102 insertions(+), 3 deletions(-) [+] |
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--- a/runtime/doc/develop.txt +++ b/runtime/doc/develop.txt @@ -1,4 +1,4 @@ -*develop.txt* For Vim version 8.0. Last change: 2017 Jul 31 +*develop.txt* For Vim version 8.0. Last change: 2018 Apr 17 VIM REFERENCE MANUAL by Bram Moolenaar @@ -185,9 +185,49 @@ 6. Make a note about what changed, prefe C COMPILER *style-compiler* The minimal C compiler version supported is C89, also known as ANSI C. -Later standards don't add much and C89 is the widest supported. +Later standards, such as C99, are not widely supported, or at least not 100% +supported. Therefore we use only some of the C99 features and disallow some +(at least for now). + +Please don't make changes everywhere to use the C99 features, it causes merge +problems for existing patches. Only use them for new and changed code. + +Comments ~ + +Traditionally Vim uses /* comments */. We intend to keep it that way, +especially for file and function headers. For new code or lines of code that +change, it is allowed to use // comments. Especially when it comes after +code: + int some_var; // single line comment useful here + +Enums ~ + +The last item in an enum may have a trailing comma. C89 didn't allow this. + +Types ~ -One restriction that this implies: no // comments, only /* comments */. +"long long" is allowed and can be expected to be 64 bits. Use %lld in printf +formats. Also "long long unsigned" with %llu. + +Flexible array members ~ + +This is an array without size, used as the last member of a struct. Vim used +to have an array of size one, which causes trouble with FORTIFY_SOURCE. Using +an "unsized array" is the intended use, we will change all of them. + struct some_stuff { + size_t length; + char payload[]; // will have size "length" + }; + +Not to be used ~ + +These C99 features are not to be used, because not enough compilers support +them: +- Declaration after Statements (MSVC 2012 does not support it). All + declarations need to be at the start of the block. +- Variable length arrays (even in C11 this is an optional feature). +- _Bool and _Complex types. +- "inline" (it's hardly ever needed, let the optimizer do its work) USE OF COMMON FUNCTIONS *style-functions*
--- a/src/auto/configure +++ b/src/auto/configure @@ -4179,6 +4179,40 @@ if test $ac_cv_header_sys_wait_h = yes; fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler can handle Vim code" >&5 +$as_echo_n "checking if the compiler can handle Vim code... " >&6; } +cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +#include <stdio.h> +int +main () +{ + + struct with_flexible_member { + int count; // comment + char text[]; // another comment + }; + enum { + one, + two, + three, + }; + long long int a = 1; + long long unsigned b = 2; + printf("a %lld and a %llu", a, b); + + ; + return 0; +} +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5 +$as_echo "yes" >&6; } +else + as_fn_error $? "compiler does not work properly - see auto/config.log" "$LINENO" 5 +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext + { $as_echo "$as_me:${as_lineno-$LINENO}: checking --enable-fail-if-missing argument" >&5 $as_echo_n "checking --enable-fail-if-missing argument... " >&6; }
--- a/src/configure.ac +++ b/src/configure.ac @@ -29,6 +29,29 @@ dnl in autoconf needs it, where it uses AC_HEADER_STDC AC_HEADER_SYS_WAIT +dnl Check that the C99 features that Vim uses are supported: +dnl - // commands +dnl - comma after last enum item +dnl - "long long int" and "long long unsigned" +dnl - flexible array member +AC_MSG_CHECKING(if the compiler can handle Vim code) +AC_TRY_COMPILE([#include <stdio.h>], [ + struct with_flexible_member { + int count; // comment + char text[]; // another comment + }; + enum { + one, + two, + three, + }; + long long int a = 1; + long long unsigned b = 2; + printf("a %lld and a %llu", a, b); + ], +AC_MSG_RESULT(yes), +AC_MSG_ERROR([compiler does not work properly - see auto/config.log])) + dnl Check for the flag that fails if stuff are missing. AC_MSG_CHECKING(--enable-fail-if-missing argument)