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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>strtok</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_009_222"> </a>NAME</h4><blockquote>strtok, strtok_r - split string into tokens</blockquote><h4><a name = "tag_000_009_223"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="string.h.html">string.h</a>>char *strtok(char *<i>s1</i>, const char *<i>s2</i>);char *strtok_r(char *<i>s</i>, const char *<i>sep</i>, char **<i>lasts</i>);</code></pre></blockquote><h4><a name = "tag_000_009_224"> </a>DESCRIPTION</h4><blockquote>A sequence of calls to<i>strtok()</i>breaks the string pointed to by<i>s1</i>into a sequence of tokens, each of which is delimited by abyte from the string pointed to by<i>s2</i>.The first call in the sequence has<i>s1</i>as its first argument, and is followed by calls with a nullpointer as their first argument.The separator string pointed to by<i>s2</i>may be different from call to call.<p>The first call in the sequence searches the string pointed to by<i>s1</i>for the first byte that is<i>not</i>contained in the current separator string pointed to by<i>s2</i>.If no such byte is found, then there are no tokens in thestring pointed to by<i>s1</i>and<i>strtok()</i>returns a null pointer. If such a byte is found, it is the start of the firsttoken.<p>The<i>strtok()</i>function then searches from there for a byte that<i>is</i>contained in the current separator string.If no such byte is found, the current token extends to theend of the string pointed to by<i>s1</i>,and subsequent searches for a token will return a null pointer.If such a byte is found, it is overwritten by anull byte, which terminates the current token.The<i>strtok()</i>function saves a pointer to the following byte, from whichthe next search for a token will start.<p>Each subsequent call, with a null pointer as the value of thefirst argument, starts searching from the saved pointer andbehaves as described above.<p>The implementation will behave as if no function defined in this documentcalls<i>strtok()</i>.<p>The<i>strtok()</i>interface need not be reentrant.<p>The function<i>strtok_r()</i>considers the null-terminated string<i>s</i>as a sequence of zero or more text tokensseparated by spans of one or more characters from the separator string<i>sep</i>.The argument<i>lasts</i>points to a user-provided pointerwhich points to stored information necessary for<i>strtok_r()</i>to continue scanning the same string.<p>In the first call to<i>strtok_r()</i>,<i>s</i>points to a null-terminated string,<i>sep</i>to a null-terminated string of separator charactersand the value pointed to by<i>lasts</i>is ignored.The function<i>strtok_r()</i>returns a pointer to the first character of the first token,writes a null character into<i>s</i>immediately following the returned token,and updates the pointer to which<i>lasts</i>points.<p>In subsequent calls,<i>s</i>is a NULL pointer and<i>lasts</i>will be unchanged from the previous callso that subsequent calls will move through the string<i>s</i>,returning successive tokens until no tokens remain.The separator string<i>sep</i>may be different from call to call.When no token remains in<i>s</i>,a NULL pointer is returned.</blockquote><h4><a name = "tag_000_009_225"> </a>RETURN VALUE</h4><blockquote>Upon successful completion,<i>strtok()</i>returns a pointer to the first byte of a token. Otherwise, if there is notoken,<i>strtok()</i>returns a null pointer.<p>The function<i>strtok_r()</i>returns a pointer to the token found,or a NULL pointer when no token is found.</blockquote><h4><a name = "tag_000_009_226"> </a>ERRORS</h4><blockquote>No errors are defined.</blockquote><h4><a name = "tag_000_009_227"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_009_228"> </a>APPLICATION USAGE</h4><blockquote>None.</blockquote><h4><a name = "tag_000_009_229"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_009_230"> </a>SEE ALSO</h4><blockquote><i><a href="string.h.html"><string.h></a></i>.</blockquote><h4>DERIVATION</h4><blockquote><i>strtok()</i> derived from Issue 1 of the SVID.<P><i>strtok_r()</i> derived from the POSIX Threads Extension (1003.1c-1995).</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
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