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<a name="getc_002d_002d_002dread-a-character-_0028macro_0029"></a>
<h3 class="section">4.33 <code>getc</code>&mdash;read a character (macro)</h3>
<a name="index-getc"></a>
<a name="index-_005fgetc_005fr"></a>
<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;stdio.h&gt;
int getc(FILE *<var>fp</var>);

#include &lt;stdio.h&gt;
int _getc_r(struct _reent *<var>ptr</var>, FILE *<var>fp</var>);

</pre></div>
<p><strong>Description</strong><br>
<code>getc</code> is a macro, defined in <code>stdio.h</code>.  You can use <code>getc</code>
to get the next single character from the file or stream
identified by <var>fp</var>.  As a side effect, <code>getc</code> advances the file&rsquo;s
current position indicator.
</p>
<p>For a subroutine version of this macro, see <code>fgetc</code>.
</p>
<p>The <code>_getc_r</code> function is simply the reentrant version of <code>getc</code>
which passes an additional reentrancy structure pointer argument: <var>ptr</var>.
</p>
<br>
<p><strong>Returns</strong><br>
The next character (read as an <code>unsigned char</code>, and cast to
<code>int</code>), unless there is no more data, or the host system reports a
read error; in either of these situations, <code>getc</code> returns <code>EOF</code>.
</p>
<p>You can distinguish the two situations that cause an <code>EOF</code> result by
using the <code>ferror</code> and <code>feof</code> functions.
</p>
<br>
<p><strong>Portability</strong><br>
ANSI C requires <code>getc</code>; it suggests, but does not require, that
<code>getc</code> be implemented as a macro.  The standard explicitly permits
macro implementations of <code>getc</code> to use the argument more than once;
therefore, in a portable program, you should not use an expression
with side effects as the <code>getc</code> argument.
</p>
<p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>,
<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>.
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