1<html lang="en"> 2<head> 3<title>gets - Untitled</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Untitled"> 6<meta name="generator" content="makeinfo 4.13"> 7<link title="Top" rel="start" href="index.html#Top"> 8<link rel="up" href="Stdio.html#Stdio" title="Stdio"> 9<link rel="prev" href="getline.html#getline" title="getline"> 10<link rel="next" href="getw.html#getw" title="getw"> 11<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 12<meta http-equiv="Content-Style-Type" content="text/css"> 13<style type="text/css"><!-- 14 pre.display { font-family:inherit } 15 pre.format { font-family:inherit } 16 pre.smalldisplay { font-family:inherit; font-size:smaller } 17 pre.smallformat { font-family:inherit; font-size:smaller } 18 pre.smallexample { font-size:smaller } 19 pre.smalllisp { font-size:smaller } 20 span.sc { font-variant:small-caps } 21 span.roman { font-family:serif; font-weight:normal; } 22 span.sansserif { font-family:sans-serif; font-weight:normal; } 23--></style> 24<link rel="stylesheet" type="text/css" href="../cs.css"> 25</head> 26<body> 27<div class="node"> 28<a name="gets"></a> 29<p> 30Next: <a rel="next" accesskey="n" href="getw.html#getw">getw</a>, 31Previous: <a rel="previous" accesskey="p" href="getline.html#getline">getline</a>, 32Up: <a rel="up" accesskey="u" href="Stdio.html#Stdio">Stdio</a> 33<hr> 34</div> 35 36<h3 class="section">4.38 <code>gets</code>—get character string (obsolete, use <code>fgets</code> instead)</h3> 37 38<p><a name="index-gets-225"></a><a name="index-g_t_005fgets_005fr-226"></a><strong>Synopsis</strong> 39<pre class="example"> #include <stdio.h> 40 41 char *gets(char *<var>buf</var>); 42 43 char *_gets_r(struct _reent *<var>reent</var>, char *<var>buf</var>); 44 45</pre> 46 <p><strong>Description</strong><br> 47Reads characters from standard input until a newline is found. 48The characters up to the newline are stored in <var>buf</var>. The 49newline is discarded, and the buffer is terminated with a 0. 50 51 <p>This is a <em>dangerous</em> function, as it has no way of checking 52the amount of space available in <var>buf</var>. One of the attacks 53used by the Internet Worm of 1988 used this to overrun a 54buffer allocated on the stack of the finger daemon and 55overwrite the return address, causing the daemon to execute 56code downloaded into it over the connection. 57 58 <p>The alternate function <code>_gets_r</code> is a reentrant version. The extra 59argument <var>reent</var> is a pointer to a reentrancy structure. 60 61 <p><br> 62<strong>Returns</strong><br> 63<code>gets</code> returns the buffer passed to it, with the data filled 64in. If end of file occurs with some data already accumulated, 65the data is returned with no other indication. If end of file 66occurs with no data in the buffer, NULL is returned. 67 68 <p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>, 69<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>. 70 71 <p><br> 72 73 </body></html> 74 75