<!-- Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009, 2013 The President and Fellows of Harvard College. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. --> <html> <head> <title>strtok</title> <body bgcolor=#ffffff> <h2 align=center>strtok</h2> <h4 align=center>OS/161 Reference Manual</h4> <h3>Name</h3> <p> strtok - tokenize string </p> <h3>Library</h3> <p> Standard C Library (libc, -lc) </p> <h3>Synopsis</h3> <p> <tt>#include <string.h></tt><br> <br> <tt>char *</tt><br> <tt>strtok(char *</tt><em>string</em><tt>, const char *</tt><em>separators</em><tt>);</tt> </p> <h3>Description</h3> <p> <tt>strtok</tt> splits up the string <em>string</em> into fields using the characters found in <em>separators</em> as delimiters. The delimiters found are discarded. Multiple delimiter characters in a row are treated as a single delimiter. </p> <p> When first called, <tt>strtok</tt> returns the first field of <em>string</em>. To retrieve successive fields of <em>string</em>, call <tt>strtok</tt> again repeatedly, passing <tt>NULL</tt> as the first argument. When no more fields are left, <tt>NULL</tt> is returned. If the string is empty or contains only delimiters, <tt>NULL</tt> will be returned on the first call. </p> <h3>Cautions</h3> <p> Note that the state used to remember <em>string</em> across calls is global. Thus, <tt>strtok</tt> cannot be used from more than one thread at a time in a multithreaded program, nor can it be used in a subroutine called from within a loop that itself uses <tt>strtok</tt>. If these restrictions are problematic, use <A HREF=strtok_r.html>strtok_r</A>. </p> <p> The behavior if strtok is called again without passing a new <em>string</em> after it has returned <tt>NULL</tt> is undefined. </p> <p> The behavior if strtok is called with the first argument <tt>NULL</tt> without having first passed a valid <em>string</em> is also undefined. </p> <h3>Return Values</h3> <p> <tt>strtok</tt> returns successive components of the passed-in string, and <tt>NULL</tt> when no more remain. </p> </body> </html>