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102 lines
4.1 KiB
HTML
102 lines
4.1 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>gets (The Red Hat newlib C Library)</title>
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<meta name="description" content="gets (The Red Hat newlib C Library)">
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<meta name="keywords" content="gets (The Red Hat newlib C Library)">
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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="getw.html#getw" rel="next" title="getw">
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</head>
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<body lang="en">
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<a name="gets"></a>
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<div class="header">
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<p>
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Next: <a href="getw.html#getw" accesskey="n" rel="next">getw</a>, Previous: <a href="getline.html#getline" accesskey="p" rel="prev">getline</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="gets_002d_002d_002dget-character-string-_0028obsolete_002c-use-fgets-instead_0029"></a>
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<h3 class="section">4.39 <code>gets</code>—get character string (obsolete, use <code>fgets</code> instead)</h3>
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<a name="index-gets"></a>
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<a name="index-_005fgets_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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char *gets(char *<var>buf</var>);
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char *_gets_r(struct _reent *<var>reent</var>, char *<var>buf</var>);
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</pre></div>
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<p><strong>Description</strong><br>
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Reads characters from standard input until a newline is found.
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The characters up to the newline are stored in <var>buf</var>. The
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newline is discarded, and the buffer is terminated with a 0.
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</p>
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<p>This is a <em>dangerous</em> function, as it has no way of checking
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the amount of space available in <var>buf</var>. One of the attacks
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used by the Internet Worm of 1988 used this to overrun a
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buffer allocated on the stack of the finger daemon and
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overwrite the return address, causing the daemon to execute
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code downloaded into it over the connection.
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</p>
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<p>The alternate function <code>_gets_r</code> is a reentrant version. The extra
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argument <var>reent</var> is a pointer to a reentrancy structure.
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</p>
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<br>
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<p><strong>Returns</strong><br>
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<code>gets</code> returns the buffer passed to it, with the data filled
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in. If end of file occurs with some data already accumulated,
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the data is returned with no other indication. If end of file
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occurs with no data in the buffer, NULL is returned.
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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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</body>
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</html>
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