136 lines
3.8 KiB
HTML
136 lines
3.8 KiB
HTML
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>isatty</title>
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<body bgcolor="white">
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<basefont size="3"> <a name="isatty"></a> <a name="tag_03_287"></a><!-- isatty -->
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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_287_01"></a>NAME</h4>
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<blockquote>isatty - test for a terminal device</blockquote>
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<h4><a name="tag_03_287_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>#include <<a href="../basedefs/unistd.h.html">unistd.h</a>><br>
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<br>
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int isatty(int</tt> <i>fildes</i><tt>);<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_287_03"></a>DESCRIPTION</h4>
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<blockquote>
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<p>The <i>isatty</i>() function shall test whether <i>fildes</i>, an open file descriptor, is associated with a terminal
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device.</p>
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</blockquote>
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<h4><a name="tag_03_287_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>The <i>isatty</i>() function shall return 1 if <i>fildes</i> is associated with a terminal; otherwise, it shall return 0 and may
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set <i>errno</i> to indicate the error.</p>
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</blockquote>
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<h4><a name="tag_03_287_05"></a>ERRORS</h4>
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<blockquote>
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<p>The <i>isatty</i>() function may fail if:</p>
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<dl compact>
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<dt>[EBADF]</dt>
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<dd>The <i>fildes</i> argument is not a valid open file descriptor.</dd>
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<dt>[ENOTTY]</dt>
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<dd>The <i>fildes</i> argument is not associated with a terminal.</dd>
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</dl>
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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_287_06"></a>EXAMPLES</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_287_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>The <i>isatty</i>() function does not necessarily indicate that a human being is available for interaction via <i>fildes</i>. It
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is quite possible that non-terminal devices are connected to the communications line.</p>
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</blockquote>
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<h4><a name="tag_03_287_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_287_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_287_10"></a>SEE ALSO</h4>
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<blockquote>
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<p>The Base Definitions volume of IEEE Std 1003.1-2001, <a href=
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"../basedefs/unistd.h.html"><i><unistd.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_287_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_287_12"></a>Issue 6</h4>
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<blockquote>
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<p>The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:</p>
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<ul>
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<li>
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<p>The optional setting of <i>errno</i> to indicate an error is added.</p>
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</li>
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<li>
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<p>The [EBADF] and [ENOTTY] optional error conditions are added.</p>
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</li>
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</ul>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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UNIX ® is a registered Trademark of The Open Group.<br>
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POSIX ® is a registered Trademark of The IEEE.<br>
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"../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>
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