1.\" Copyright (c) 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" from: @(#)strtok.3 8.2 (Berkeley) 2/3/94 37.\" $NetBSD: strtok.3,v 1.15 2002/02/07 07:00:33 ross Exp $ 38.\" 39.Dd February 3, 1994 40.Dt STRTOK 3 41.Os 42.Sh NAME 43.Nm strtok, strtok_r 44.Nd string tokens 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.Fd #include \*[Lt]string.h\*[Gt] 49.Ft char * 50.Fn strtok "char * restrict str" "const char * restrict sep" 51.Ft char * 52.Fn strtok_r "char *str" "const char *sep" "char **lasts" 53.Sh DESCRIPTION 54The 55.Fn strtok 56function 57is used to isolate sequential tokens in a null-terminated string, 58.Fa str . 59These tokens are separated in the string by at least one of the 60characters in 61.Fa sep . 62The first time that 63.Fn strtok 64is called, 65.Fa str 66should be specified; subsequent calls, wishing to obtain further tokens 67from the same string, should pass a null pointer instead. 68The separator string, 69.Fa sep , 70must be supplied each time, and may change between calls. 71.Pp 72The 73.Fn strtok 74function 75returns a pointer to the beginning of each subsequent token in the string, 76after replacing the separator character itself with a 77.Dv NUL 78character. 79Separator characters at the beginning of the string or at the 80continuation point are skipped so that zero length tokens 81are not returned. 82When no more tokens remain, a null pointer is returned. 83.Pp 84The 85.Fn strtok_r 86function implements the functionality of 87.Fn strtok 88but is passed an additional argument, 89.Fa lasts , 90which points to a user-provided pointer which is used by 91.Fn strtok_r 92to store state which needs to be kept between calls to scan the same string; 93unlike 94.Fn strtok , 95it is not necessary to delineate tokenizing to a single string at a time 96when using 97.Fn strtok_r . 98.Sh SEE ALSO 99.Xr index 3 , 100.Xr memchr 3 , 101.Xr rindex 3 , 102.Xr strchr 3 , 103.Xr strcspn 3 , 104.Xr strpbrk 3 , 105.Xr strrchr 3 , 106.Xr strsep 3 , 107.Xr strspn 3 , 108.Xr strstr 3 109.Sh STANDARDS 110The 111.Fn strtok 112function 113conforms to 114.St -ansiC . 115The 116.Fn strtok_r 117function conforms to 118.St -p1003.1c-95 . 119.Sh BUGS 120There is no way to get tokens from multiple strings simultaneously. 121.Pp 122The System V 123.Fn strtok , 124if handed a string containing only delimiter characters, 125will not alter the next starting point, so that a call to 126.Fn strtok 127with a different (or empty) delimiter string 128may return a 129.Pf non- Dv NULL 130value. 131Since this implementation always alters the next starting point, 132such a sequence of calls would always return 133.Dv NULL . 134