'\" te
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.TH re_comp 3C "26 Feb 1997" "SunOS 5.11" "Standard C Library Functions"
.SH NAME
re_comp, re_exec \- compile and execute regular expressions
.SH SYNOPSIS
.LP
.nf
#include <re_comp.h>

\fBchar *\fR\fBre_comp\fR(\fBconst char *\fR\fIstring\fR);
.fi

.LP
.nf
\fBint\fR \fBre_exec\fR(\fBconst char *\fR\fIstring\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBre_comp()\fR function converts a regular expression string (RE) into an internal form suitable for pattern matching.  The \fBre_exec()\fR function compares the string pointed to by the \fIstring\fR argument with the last regular expression passed to \fBre_comp()\fR.
.sp
.LP
If \fBre_comp()\fR is called with a null pointer argument, the current regular expression remains unchanged.
.sp
.LP
Strings passed to both \fBre_comp()\fR and \fBre_exec()\fR must be terminated by a null byte, and may include \fBNEWLINE\fR characters.
.sp
.LP
The \fBre_comp()\fR and \fBre_exec()\fR functions support \fIsimple regular expressions\fR, which are defined on the \fBregexp\fR(5) manual page. The  regular expressions of the form \fB\e{\fRm\fB\e}\fR, \fB\e{\fRm,\fB\e}\fR, or \fB\e{\fRm,n\fB\e}\fR are not supported.
.SH RETURN VALUES
.sp
.LP
The \fBre_comp()\fR function returns a null pointer when the string pointed to by the \fIstring\fR argument is successfully converted.  Otherwise, a pointer to one of the following error message strings is returned:
.sp
.in +2
.nf
No previous regular expression
Regular expression too long
unmatched \e\|(
missing ]
too many \e\|(\|\e\|) pairs
unmatched \e\|)
.fi
.in -2

.sp
.LP
Upon successful completion, \fBre_exec()\fR returns \fB1\fR if \fIstring\fR matches the last compiled regular expression.  Otherwise, \fBre_exec()\fR returns \fB0\fR if \fIstring\fR fails to match the last compiled regular expression, and \fB\(mi1\fR if the compiled regular expression is invalid (indicating an internal error).
.SH ERRORS
.sp
.LP
No errors are defined.
.SH USAGE
.sp
.LP
For portability to implementations conforming to X/Open standards prior to SUS, \fBregcomp\fR(3C) and \fBregexec\fR(3C) are preferred to these functions.  See \fBstandards\fR(5).
.SH SEE ALSO
.sp
.LP
\fBgrep\fR(1), \fBregcmp\fR(1), \fBregcmp\fR(3C), \fBregcomp\fR(3C), \fBregexec\fR(3C), \fBregexpr\fR(3GEN), \fBregexp\fR(5), \fBstandards\fR(5)