NAME
re_comp, re_exec - regular expression handler

SYNOPSIS
char *re_comp(s)
const char *s;

int re_exec(s)
const 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 0 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 nulls. The
regular expressions recognized are described in the manual entry
for ed(1), given the above difference.

SEE ALSO
ed(1), ex(1), egrep(1), fgrep(1), grep(1), regexp(3)

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 .