Copyright (c) 1998 Softweyr LLC. All rights reserved.

 strtok_r, from Berkeley strtok
 Oct 13, 1998 by Wes Peters <wes@softweyr.com>

 Copyright (c) 1988, 1991, 1993
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 This code is derived from software contributed to Berkeley by
 the American National Standards Committee X3, on Information
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 @(#)strtok.3 8.2 (Berkeley) 2/3/94
 $FreeBSD: releng/11.0/lib/libc/string/strtok.3 294597 2016-01-22 20:36:03Z wblock $

.Dd January 22, 2016
.Dt STRTOK 3
.Os
.Sh NAME
.Nm strtok , strtok_r
.Nd string tokens
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
n string.h .Ft char *
.Fn strtok "char *str" "const char *sep"
.Ft char *
.Fn strtok_r "char *str" "const char *sep" "char **last"
.Sh DESCRIPTION
f -symbolic This interface is obsoleted by
.Xr strsep 3 .
.Ef

p
The
.Fn strtok
function
is used to isolate sequential tokens in a null-terminated string,
.Fa str .
These tokens are separated in the string by at least one of the
characters in
.Fa sep .
The first time that
.Fn strtok
is called,
.Fa str
should be specified; subsequent calls, wishing to obtain further tokens
from the same string, should pass a null pointer instead.
The separator string,
.Fa sep ,
must be supplied each time, and may change between calls.

p
The implementation will behave as if no library function calls
.Fn strtok .

p
The
.Fn strtok_r
function is a reentrant version of
.Fn strtok .
The context pointer
.Fa last
must be provided on each call.
The
.Fn strtok_r
function
may also be used to nest two parsing loops within one another, as
long as separate context pointers are used.

p
The
.Fn strtok
and
.Fn strtok_r
functions
return a pointer to the beginning of each subsequent token in the string,
after replacing the token itself with a
.Dv NUL
character.
When no more tokens remain, a null pointer is returned.
.Sh EXAMPLES
The following uses
.Fn strtok_r
to parse two strings using separate contexts:
d -literal char test[80], blah[80];
char *sep = "\e\e/:;=-";
char *word, *phrase, *brkt, *brkb;

strcpy(test, "This;is.a:test:of=the/string\e\etokenizer-function.");

for (word = strtok_r(test, sep, &brkt);
 word;
 word = strtok_r(NULL, sep, &brkt))
{
 strcpy(blah, "blah:blat:blab:blag");

 for (phrase = strtok_r(blah, sep, &brkb);
 phrase;
 phrase = strtok_r(NULL, sep, &brkb))
 {
 printf("So far we're at %s:%s\en", word, phrase);
 }
}
.Ed
.Sh SEE ALSO
.Xr memchr 3 ,
.Xr strchr 3 ,
.Xr strcspn 3 ,
.Xr strpbrk 3 ,
.Xr strrchr 3 ,
.Xr strsep 3 ,
.Xr strspn 3 ,
.Xr strstr 3 ,
.Xr wcstok 3
.Sh STANDARDS
The
.Fn strtok
function
conforms to
.St -isoC .
The
.Fn strtok_r
function
conforms to
.St -p1003.1-2001 .
.Sh AUTHORS
.An Wes Peters Aq Mt wes@softweyr.com ,
Softweyr LLC

p
Based on the
.Fx 3.0
implementation.
.Sh BUGS
The System V
.Fn strtok ,
if handed a string containing only delimiter characters,
will not alter the next starting point, so that a call to
.Fn strtok
with a different (or empty) delimiter string
may return a

f non- Dv NULL
value.
Since this implementation always alters the next starting point,
such a sequence of calls would always return
.Dv NULL .