121 lines
4.2 KiB
HTML
121 lines
4.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<meta name="generator" content="HTML Tidy, see www.w3.org">
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<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>getc</title>
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</head>
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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="getc"></a> <a name="tag_03_210"></a><!-- getc -->
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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_210_01"></a>NAME</h4>
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<blockquote>getc - get a byte from a stream</blockquote>
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<h4><a name="tag_03_210_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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int getc(FILE *</tt><i>stream</i><tt>);<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_210_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>getc</i>() function shall be equivalent to <a href="fgetc.html"><i>fgetc</i>()</a> , except that if it is implemented as
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a macro it may evaluate <i>stream</i> more than once, so the argument should never be an expression with side effects.</p>
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</blockquote>
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<h4><a name="tag_03_210_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>Refer to <a href="fgetc.html"><i>fgetc</i>()</a> .</p>
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</blockquote>
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<h4><a name="tag_03_210_05"></a>ERRORS</h4>
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<blockquote>
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<p>Refer to <a href="fgetc.html"><i>fgetc</i>()</a> .</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_210_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_210_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>If the integer value returned by <i>getc</i>() is stored into a variable of type <b>char</b> and then compared against the
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integer constant EOF, the comparison may never succeed, because sign-extension of a variable of type <b>char</b> on widening to
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integer is implementation-defined.</p>
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<p>Since it may be implemented as a macro, <i>getc</i>() may treat incorrectly a <i>stream</i> argument with side effects. In
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particular, <i>getc</i>(*<i>f</i>++) does not necessarily work as expected. Therefore, use of this function should be preceded by
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<tt>"#undef getc"</tt> in such situations; <a href="../functions/fgetc.html"><i>fgetc</i>()</a> could also be used.</p>
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</blockquote>
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<h4><a name="tag_03_210_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_210_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_210_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="fgetc.html"><i>fgetc</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a href=
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"../basedefs/stdio.h.html"><i><stdio.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_210_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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<div class="box"><em>End of informative text.</em></div>
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POSIX ® is a registered Trademark of The IEEE.<br>
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