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Manual Pages  — RE_COMP


re_comp, re_exec – regular expression handler



Compatibility Library (libcompat, -lcompat)


#include <unistd.h>

char *
re_comp(const char *s);

re_exec(const char *s);


This interface is made obsolete by regex(3).

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.


The re_exec() function returns -1 for an internal error.

The re_comp() function returns "no previous regular expression" or one of the strings generated by regerror(3).


ed(1), egrep(1), ex(1), fgrep(1), grep(1), regex(3)


The re_comp() and re_exec() functions appeared in BSD 4.0 .

RE_COMP (3) June 4, 1993

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