RE_COMP(3) Linux Programmer's Manual RE_COMP(3)

re_comp, re_exec - 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.

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).
Interface Attribute Value
re_comp (), re_exec () Thread safety MT-Unsafe

4.3BSD.

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

regcomp(3), regex(7), GNU regex manual
2017-09-15 GNU