re_comp - Man Page

BSD regex functions


#define _REGEX_RE_COMP
#include <sys/types.h>
#include <regex.h>

char *re_comp(const char *regex);
int re_exec(const char *string);


re_comp() is used to compile the null-terminated regular expression pointed to by regex. The compiled pattern occupies a static area, the pattern buffer, which is overwritten by subsequent use of re_comp(). If regex is NULL, no operation is performed and the pattern buffer's contents are not altered.

re_exec() is used to assess whether the null-terminated string pointed to by string matches the previously compiled regex.

Return Value

re_comp() returns NULL on successful compilation of regex otherwise it returns a pointer to an appropriate error message.

re_exec() returns 1 for a successful match, zero for failure.


For an explanation of the terms used in this section, see attributes(7).

re_comp(), re_exec()Thread safetyMT-Unsafe

Conforming to



These functions are obsolete; the functions documented in regcomp(3) should be used instead.

See Also

regcomp(3), regex(7), GNU regex manual


This page is part of release 5.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at

Referenced By


The man page re_exec(3) is an alias of re_comp(3).

2021-03-22 GNU Linux Programmer's Manual