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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2004 IEEE and The Open Group, All Rights Reserved --><title>gets</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="gets"></a> <a name="tag_03_248"></a><!-- gets --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2004 Edition<br>Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_248_01"></a>NAME</h4><blockquote>gets - get a string from a stdin stream</blockquote><h4><a name="tag_03_248_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/stdio.h.html">stdio.h</a>><br><br> char *gets(char *</tt><i>s</i><tt>);<br></tt></code></p></blockquote><h4><a name="tag_03_248_03"></a>DESCRIPTION</h4><blockquote><div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between therequirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers tothe ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div><p>The <i>gets</i>() function shall read bytes from the standard input stream, <i>stdin</i>, into the array pointed to by <i>s</i>,until a <newline> is read or an end-of-file condition is encountered. Any <newline> shall be discarded and a null byteshall be placed immediately after the last byte read into the array.</p><p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> The<i>gets</i>() function may mark the <i>st_atime</i> field of the file associated with <i>stream</i> for update. The <i>st_atime</i>field shall be marked for update by the first successful execution of <a href="../functions/fgetc.html"><i>fgetc</i>()</a>, <ahref="../functions/fgets.html"><i>fgets</i>()</a>, <a href="../functions/fread.html"><i>fread</i>()</a>, <a href="../functions/getc.html"><i>getc</i>()</a>, <a href="../functions/getchar.html"><i>getchar</i>()</a>, <i>gets</i>(), <a href="../functions/fscanf.html"><i>fscanf</i>()</a>, or <a href="../functions/scanf.html"><i>scanf</i>()</a> using <i>stream</i> thatreturns data not supplied by a prior call to <a href="../functions/ungetc.html"><i>ungetc</i>()</a>. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p></blockquote><h4><a name="tag_03_248_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, <i>gets</i>() shall return <i>s</i>. If the stream is at end-of-file, the end-of-file indicator forthe stream shall be set and <i>gets</i>() shall return a null pointer. If a read error occurs, the error indicator for the streamshall be set, <i>gets</i>() shall return a null pointer, <sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> and set <i>errno</i> to indicate the error. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p></blockquote><h4><a name="tag_03_248_05"></a>ERRORS</h4><blockquote><p>Refer to <a href="fgetc.html"><i>fgetc</i>()</a>.</p></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_248_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_248_07"></a>APPLICATION USAGE</h4><blockquote><p>Reading a line that overflows the array pointed to by <i>s</i> results in undefined behavior. The use of <a href="../functions/fgets.html"><i>fgets</i>()</a> is recommended.</p><p>Since the user cannot specify the length of the buffer passed to <i>gets</i>(), use of this function is discouraged. The lengthof the string read is unlimited. It is possible to overflow this buffer in such a way as to cause applications to fail, or possiblesystem security violations.</p><p>It is recommended that the <a href="../functions/fgets.html"><i>fgets</i>()</a> function should be used to read input lines.</p></blockquote><h4><a name="tag_03_248_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_248_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_248_10"></a>SEE ALSO</h4><blockquote><p><a href="feof.html"><i>feof</i>()</a>, <a href="ferror.html"><i>ferror</i>()</a>, <a href="fgets.html"><i>fgets</i>()</a>,the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/stdio.h.html"><i><stdio.h></i></a></p></blockquote><h4><a name="tag_03_248_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 1. Derived from Issue 1 of the SVID.</p></blockquote><h4><a name="tag_03_248_12"></a>Issue 6</h4><blockquote><p>Extensions beyond the ISO C standard are marked.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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