This interface is made obsolete by
regex(3). It is available from the compatibility library, libcompat.
The
re_comp() function compiles a string into an internal form suitable for pattern matching. The
re_exec() function checks the argument string against the last string passed to
re_comp().
The
re_comp() function 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.
The
re_exec() function 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
NULs. The regular expressions recognized are described in the manual entry for
ed(1), given the above difference.