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130 lines
5.5 KiB
HTML
130 lines
5.5 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>fgetc (The Red Hat newlib C Library)</title>
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<meta name="description" content="fgetc (The Red Hat newlib C Library)">
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<meta name="keywords" content="fgetc (The Red Hat newlib C Library)">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Document-Index.html#Document-Index" rel="index" title="Document Index">
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<link href="Document-Index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Stdio.html#Stdio" rel="up" title="Stdio">
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<link href="fgetpos.html#fgetpos" rel="next" title="fgetpos">
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</head>
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<body lang="en">
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<a name="fgetc"></a>
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<div class="header">
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<p>
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Next: <a href="fgetpos.html#fgetpos" accesskey="n" rel="next">fgetpos</a>, Previous: <a href="fflush.html#fflush" accesskey="p" rel="prev">fflush</a>, Up: <a href="Stdio.html#Stdio" accesskey="u" rel="up">Stdio</a> [<a href="Document-Index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Document-Index.html#Document-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="fgetc_002c-fgetc_005funlocked_002d_002d_002dget-a-character-from-a-file-or-stream"></a>
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<h3 class="section">4.10 <code>fgetc</code>, <code>fgetc_unlocked</code>—get a character from a file or stream</h3>
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<a name="index-fgetc"></a>
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<a name="index-fgetc_005funlocked"></a>
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<a name="index-_005ffgetc_005fr"></a>
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<a name="index-_005ffgetc_005funlocked_005fr"></a>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">#include <stdio.h>
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int fgetc(FILE *<var>fp</var>);
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#define _BSD_SOURCE
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#include <stdio.h>
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int fgetc_unlocked(FILE *<var>fp</var>);
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#include <stdio.h>
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int _fgetc_r(struct _reent *<var>ptr</var>, FILE *<var>fp</var>);
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#define _BSD_SOURCE
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#include <stdio.h>
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int _fgetc_unlocked_r(struct _reent *<var>ptr</var>, FILE *<var>fp</var>);
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</pre></div>
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<p><strong>Description</strong><br>
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Use <code>fgetc</code> to get the next single character from the file or stream
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identified by <var>fp</var>. As a side effect, <code>fgetc</code> advances the file’s
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current position indicator.
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</p>
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<p>For a macro version of this function, see <code>getc</code>.
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</p>
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<p><code>fgetc_unlocked</code> is a non-thread-safe version of <code>fgetc</code>.
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<code>fgetc_unlocked</code> may only safely be used within a scope
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protected by flockfile() (or ftrylockfile()) and funlockfile(). This
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function may safely be used in a multi-threaded program if and only
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if they are called while the invoking thread owns the (FILE *)
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object, as is the case after a successful call to the flockfile() or
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ftrylockfile() functions. If threads are disabled, then
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<code>fgetc_unlocked</code> is equivalent to <code>fgetc</code>.
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</p>
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<p>The functions <code>_fgetc_r</code> and <code>_fgetc_unlocked_r</code> are simply reentrant
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versions that are passed the additional reentrant structure pointer
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argument: <var>ptr</var>.
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</p>
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<br>
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<p><strong>Returns</strong><br>
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The next character (read as an <code>unsigned char</code>, and cast to
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<code>int</code>), unless there is no more data, or the host system reports a
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read error; in either of these situations, <code>fgetc</code> returns <code>EOF</code>.
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</p>
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<p>You can distinguish the two situations that cause an <code>EOF</code> result by
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using the <code>ferror</code> and <code>feof</code> functions.
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</p>
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<br>
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<p><strong>Portability</strong><br>
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ANSI C requires <code>fgetc</code>.
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</p>
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<p><code>fgetc_unlocked</code> is a BSD extension also provided by GNU libc.
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</p>
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<p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>,
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<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>.
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</p>
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<br>
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<hr>
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<div class="header">
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<p>
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Next: <a href="fgetpos.html#fgetpos" accesskey="n" rel="next">fgetpos</a>, Previous: <a href="fflush.html#fflush" accesskey="p" rel="prev">fflush</a>, Up: <a href="Stdio.html#Stdio" accesskey="u" rel="up">Stdio</a> [<a href="Document-Index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Document-Index.html#Document-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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</body>
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</html>
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