Copyright (c) 1980 Regents of the University of California.
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@(#)re_comp.3 6.1 (Berkeley) 05/15/85

C re_comp, re_exec - regular expression handler char *re_comp(s)

char *s;

re_exec(s)

char *s;

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.

ed(1), ex(1), egrep(1), fgrep(1), grep(1) 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 \e(,
missing ],
too many \e(\e) pairs,
unmatched \e).