commit https://github.com/vim/vim/commit/3bece9fee9c02934d3e295b29d253e13d4ef26a7 Author: Bram Moolenaar <Bram@vim.org> Date: Mon Feb 15 20:39:46 2016 +0100 patch 7.4.1322 Problem: Crash when unletting the variable that holds the channel in a callback function. (Christian Robinson) Solution: Increase the reference count while invoking the callback.

/*
 * if_sniff.h Interface between Vim and SNiFF+
 */

#ifndef __if_sniff_h__
#define __if_sniff_h__

extern int  want_sniff_request;
extern int  sniff_request_waiting;
extern int  sniff_connected;
extern int  fd_from_sniff;
extern void sniff_disconnect(int immediately);
extern void ProcessSniffRequests(void);
extern void ex_sniff(exarg_T *eap);

#endif