REGEX(3)
NAME
re_comp, re_exec − regular expression handler
USAGE
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 zero if the string s was compiled successfully; otherwise a string containing an error message is returned. If re_comp is passed zero or a null string, it returns without changing the currently compiled regular expression.
Re_exec returns one if the string s matches the last compiled regular expression, zero 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 nulls. The regular expressions recognized are described in the manual entry for ed(1), given the above difference.
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 \).