.\" $OpenBSD: strsep.3,v 1.4 1998/06/15 17:55:14 mickey Exp $
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.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek.
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.\"	@(#)strsep.3	8.1 (Berkeley) 6/9/93
.\"
.Dd June 9, 1993
.Dt STRSEP 3
.Os
.Sh NAME
.Nm strsep
.Nd separate strings
.Sh SYNOPSIS
.Fd #include <string.h>
.Ft char *
.Fn strsep "char **stringp" "char *delim"
.Sh DESCRIPTION
The
.Fn strsep
function locates, in the string referenced by
.Fa *stringp ,
the first occurrence of any character in the string
.Fa delim
(or the terminating
.Ql \e0
character) and replaces it with a
.Ql \e0 .
The location of the next character after the delimiter character
(or NULL, if the end of the string was reached) is stored in
.Fa *stringp .
The original value of
.Fa *stringp
is returned.
.Pp
An ``empty'' field, i.e. one caused by two adjacent delimiter characters,
can be detected by comparing the location referenced by the pointer returned
in
.Fa *stringp
to
.Ql \e0 .
.Pp
If
.Fa *stringp
is initially
.Dv NULL ,
.Fn strsep
returns
.Dv NULL .
.Sh EXAMPLES
The following uses
.Fn strsep
to parse a string, containing tokens delimited by white space, into an
argument vector:
.Bd -literal -offset indent
char **ap, *argv[10], *inputstring;

for (ap = argv; (*ap = strsep(&inputstring, " \et")) != NULL;)
	if (**ap != '\e0')
		++ap;
.Ed
.Sh HISTORY
The
.Fn strsep
function
is intended as a replacement for the
.Fn strtok
function.
While the
.Fn strtok
function should be preferred for portability reasons (it conforms to
.St -ansiC )
it is unable to handle empty fields, i.e. detect fields delimited by
two adjacent delimiter characters, or to be used for more than a single
string at a time.
The
.Fn strsep
function first appeared in
.Bx 4.4 .