REGEX(3)

NAME
regex, re_comp, re_exec - regular expression handler

SYNOPSIS
char *re_comp(s)
char *s;

re_exec(s)
char *s;

DESCRIPTION

re_comp() compiles a string into an internal form suitable for pattern matching. re_exec() checks the argument string against the last string passed to re_comp().

re_comp() returns a NULL pointer if the string s was compiled successfully; otherwise a string containing an error message is returned. If re_comp() is passed 0 or a null string, it returns without changing the currently compiled regular expression.

re_exec() returns 1 if the string s matches the last compiled regular expression, 0 if the string s failed to match the last compiled regular expression, and -1 if the compiled regular expression was invalid (indicating an internal error).

The strings passed to both re_comp() and re_exec() may have trailing or embedded NEWLINE characters; they are terminated by null characters. The regular expressions recognized are described in the manual entry for ed(1), given the above difference.

SEE ALSO
ed(1), ex(1), grep(1V)

DIAGNOSTICS

re_exec() returns -1 for an internal error.

re_comp() returns one of the following strings if an error occurs:

No previous regular expression

Regular expression too long

unmatched \(

missing ]

too many \(\) pairs

unmatched \)