os161 / man / libc / strtok.html
strtok.html
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<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 &lt;string.h&gt;</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>