NAME

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 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)

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 \).

4BSD