(BSD System Compatibility)

regex(3bsd)

regex: re_comp, re_exec -- (BSD) regular expression handler

Synopsis

   /usr/ucb/cc [flag . . . ] file . . .
   
   char *re_comp(char *s);
   

   re_exec(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 page entry for ed(1), given the above difference.

<Return> values

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 \)

References

ed(1), ex(1), grep(1), regcmp(1), regcmp(3G), regexp(5), regexpr(3G)