.TH RGXG_UTILS_ESCAPE_STRING 3 "Apr 12, 2020" "rgxg 0.1.2" "librgxg manual"
.SH NAME
rgxg_utils_escape_string \- escape the given string for use in a regular expression

.SH SYNOPSIS
.nf
.B #include <rgxg/utils.h>

.BI "int rgxg_utils_escape_string (const char *" src ", size_t " size ,
.ti +5n
.BI "char *" regex ", rgxg_options_t " options );
.fi

.SH DESCRIPTION
.BR rgxg_utils_escape_string ()
generates the (extended) regular expression that matches at most
.I size
bytes (or up to the first null byte) of the given string
.IR src ,
by escaping the regular expression special characters.
.I src
must be valid and not NULL.

The generated regular expression is written to the character string
.IR regex ,
including the terminating null byte ('\\0'), unless
.B RGXG_NONULLBYTE
is set. If
.I regex
is NULL the return value is the number of characters (excluding the terminating null byte) that would have been written in case
.I regex
has been initialized. Note that the functions assume an arbitrarily long
.I regex
string, callers must
.B ensure
that the given string is large enough to not overflow the actual space.

.I options
is either zero, or set to the following macro:

.TP
.B RGXG_NONULLBYTE
Do not add the terminating null byte ('\\0') to the
.I regex
string.

.SH "RETURN VALUE"
.BR rgxg_utils_escape_string ()
returns the number of characters (excluding the terminating null byte) written to
.IR regex .

.SH AVAILABILITY
This function is available since rgxg 0.1.

.SH SEE ALSO
.BR regex (7),
.BR rgxg_utils_alternation (3).

.SH AUTHOR
Hannes von Haugwitz <hannes@vonhaugwitz.com>