📄 select.h.html
字号:
<!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) 2001-2003 The Open Group, All Rights Reserved --><title><sys/select.h></title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../../jscript/dotcode.js"></script><basefont size="3"> <a name="<sys/select.h>"></a> <a name="tag_13_58"></a><!-- <sys/select.h> --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_13_58_01"></a>NAME</h4><blockquote>sys/select.h - select types</blockquote><h4><a name="tag_13_58_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><tt>#include <sys/select.h></tt></p></blockquote><h4><a name="tag_13_58_03"></a>DESCRIPTION</h4><blockquote><p>The <i><sys/select.h></i> header shall define the <b>timeval</b> structure that includes at least the followingmembers:</p><pre><tt>time_t tv_sec </tt> Seconds. <tt>suseconds_t tv_usec </tt> Microseconds. <tt></tt></pre><p>The <b>time_t</b> and <b>suseconds_t</b> types shall be defined as described in <a href="../sys/types.h.html#tag_13_67"><i><sys/types.h></i></a> .</p><p>The <b>sigset_t</b> type shall be defined as described in <a href="../signal.h.html#"><i><signal.h></i></a> .</p><p>The <b>timespec</b> structure shall be defined as described in <a href="time.h.html"><i><time.h></i></a> .</p><p>The <i><sys/select.h></i> header shall define the <b>fd_set</b> type as a structure.</p><p>Each of the following may be declared as a function, or defined as a macro, or both:</p><dl compact><dt><b>void</b> <i>FD_CLR</i>(<b>int</b> <i>fd</i>, <b>fd_set *</b><i>fdset</i>)</dt><dd><br>Clears the bit for the file descriptor <i>fd</i> in the file descriptor set <i>fdset</i>.</dd><dt><b>int</b> <i>FD_ISSET</i>(<b>int</b> <i>fd</i>, <b>fd_set *</b><i>fdset</i>)</dt><dd><br>Returns a non-zero value if the bit for the file descriptor <i>fd</i> is set in the file descriptor set by <i>fdset</i>, and 0otherwise.</dd><dt><b>void</b> <i>FD_SET</i>(<b>int</b> <i>fd</i>, <b>fd_set *</b><i>fdset</i>)</dt><dd><br>Sets the bit for the file descriptor <i>fd</i> in the file descriptor set <i>fdset</i>.</dd><dt><b>void</b> <i>FD_ZERO</i>(<b>fd_set *</b><i>fdset</i>)</dt><dd><br>Initializes the file descriptor set <i>fdset</i> to have zero bits for all file descriptors.</dd></dl><p>If implemented as macros, these may evaluate their arguments more than once, so applications should ensure that the argumentsthey supply are never expressions with side effects.</p><p>The following shall be defined as a macro:</p><dl compact><dt>FD_SETSIZE</dt><dd><br>Maximum number of file descriptors in an <b>fd_set</b> structure.</dd></dl><p>The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.</p><pre><tt>int pselect(int, fd_set *restrict, fd_set *restrict, fd_set *restrict, const struct timespec *restrict, const sigset_t *restrict);int select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict, struct timeval *restrict);</tt></pre><p>Inclusion of the <i><sys/select.h></i> header may make visible all symbols from the headers <a href="../../basedefs/signal.h.html"><i><signal.h></i></a>, <a href="../../basedefs/sys/time.h.html"><i><sys/time.h></i></a>,and <a href="../../basedefs/time.h.html"><i><time.h></i></a>.</p></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_13_58_04"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_13_58_05"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_13_58_06"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_13_58_07"></a>SEE ALSO</h4><blockquote><p><a href="../signal.h.html#"><i><signal.h></i></a> , <a href="../sys/time.h.html#tag_13_64"><i><sys/time.h></i></a> ,<a href="../sys/types.h.html#tag_13_67"><i><sys/types.h></i></a> , <a href="time.h.html"><i><time.h></i></a> , theSystem Interfaces volume of IEEE Std 1003.1-2001, <a href="../../functions/pselect.html"><i>pselect</i>()</a>, <a href="../../functions/select.html"><i>select</i>()</a></p></blockquote><h4><a name="tag_13_58_08"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 6. Derived from IEEE Std 1003.1g-2000.</p><p>The requirement for the <b>fd_set</b> structure to have a member <i>fds_bits</i> has been removed as per The Open Group BaseResolution bwg2001-005.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr><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
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -