165 lines
6.2 KiB
HTML
165 lines
6.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>tmpnam</title>
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<body bgcolor="white">
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<script type="text/javascript" language="JavaScript" src="../jscript/codes.js">
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<basefont size="3"> <a name="tmpnam"></a> <a name="tag_03_782"></a><!-- tmpnam -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_782_01"></a>NAME</h4>
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<blockquote>tmpnam - create a name for a temporary file</blockquote>
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<h4><a name="tag_03_782_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>#include <<a href="../basedefs/stdio.h.html">stdio.h</a>><br>
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<br>
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char *tmpnam(char *</tt><i>s</i><tt>);<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_782_03"></a>DESCRIPTION</h4>
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<blockquote>
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<div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"
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border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the
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requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to
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the ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div>
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<p>The <i>tmpnam</i>() function shall generate a string that is a valid filename and that is not the same as the name of an
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existing file. The function is potentially capable of generating {TMP_MAX} different strings, but any or all of them may already be
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in use by existing files and thus not be suitable return values.</p>
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<p>The <i>tmpnam</i>() function generates a different string each time it is called from the same process, up to {TMP_MAX} times.
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If it is called more than {TMP_MAX} times, the behavior is implementation-defined.</p>
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<p>The implementation shall behave as if no function defined in this volume of IEEE Std 1003.1-2001 calls
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<i>tmpnam</i>().</p>
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<p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> If
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the application uses any of the functions guaranteed to be available if either _POSIX_THREAD_SAFE_FUNCTIONS or _POSIX_THREADS is
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defined, the application shall ensure that the <i>tmpnam</i>() function is called with a non-NULL parameter. <img src=
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"../images/opt-end.gif" alt="[Option End]" border="0"></p>
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</blockquote>
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<h4><a name="tag_03_782_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>Upon successful completion, <i>tmpnam</i>() shall return a pointer to a string. If no suitable string can be generated, the
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<i>tmpnam</i>() function shall return a null pointer.</p>
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<p>If the argument <i>s</i> is a null pointer, <i>tmpnam</i>() shall leave its result in an internal static object and return a
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pointer to that object. Subsequent calls to <i>tmpnam</i>() may modify the same object. If the argument <i>s</i> is not a null
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pointer, it is presumed to point to an array of at least L_tmpnam <b>char</b>s; <i>tmpnam</i>() shall write its result in that
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array and shall return the argument as its value.</p>
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</blockquote>
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<h4><a name="tag_03_782_05"></a>ERRORS</h4>
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<blockquote>
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<p>No errors are defined.</p>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_782_06"></a>EXAMPLES</h4>
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<blockquote>
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<h5><a name="tag_03_782_06_01"></a>Generating a Filename</h5>
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<p>The following example generates a unique filename and stores it in the array pointed to by <i>ptr</i>.</p>
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<pre>
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<tt>#include <stdio.h>
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...
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char filename[L_tmpnam+1];
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char *ptr;
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<br>
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ptr = tmpnam(filename);
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</tt>
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</pre>
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</blockquote>
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<h4><a name="tag_03_782_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>This function only creates filenames. It is the application's responsibility to create and remove the files.</p>
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<p>Between the time a pathname is created and the file is opened, it is possible for some other process to create a file with the
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same name. Applications may find <a href="../functions/tmpfile.html"><i>tmpfile</i>()</a> more useful.</p>
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</blockquote>
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<h4><a name="tag_03_782_08"></a>RATIONALE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_782_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_782_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="fopen.html"><i>fopen</i>()</a> , <a href="open.html"><i>open</i>()</a> , <a href="tempnam.html"><i>tempnam</i>()</a> ,
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<a href="tmpfile.html"><i>tmpfile</i>()</a> , <a href="unlink.html"><i>unlink</i>()</a> , the Base Definitions volume of
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IEEE Std 1003.1-2001, <a href="../basedefs/stdio.h.html"><i><stdio.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_782_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 1. Derived from Issue 1 of the SVID.</p>
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</blockquote>
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<h4><a name="tag_03_782_12"></a>Issue 5</h4>
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<blockquote>
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<p>The DESCRIPTION is updated for alignment with the POSIX Threads Extension.</p>
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</blockquote>
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<h4><a name="tag_03_782_13"></a>Issue 6</h4>
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<blockquote>
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<p>Extensions beyond the ISO C standard are marked.</p>
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<p>The DESCRIPTION is updated to avoid use of the term "must" for application requirements.</p>
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<p>The DESCRIPTION is expanded for alignment with the ISO/IEC 9899:1999 standard.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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