📄 systime.h.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title><sys/time.h></title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_009_369"> </a>NAME</h4><blockquote>sys/time.h - time types</blockquote><h4><a name = "tag_000_009_370"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <sys/time.h></code></pre></blockquote><h4><a name = "tag_000_009_371"> </a>DESCRIPTION</h4><blockquote>The<i><sys/time.h></i>header defines the<b>timeval</b>structure that includes at least the following members:<pre><code>time_t tv_sec secondssuseconds_t tv_usec microseconds</code></pre><p>The<i><sys/time.h></i>header defines the<b>itimerval</b>structure that includes at least the following members:<pre><code>struct timeval it_interval timer intervalstruct timeval it_value current value</code></pre><p>The<b>time_t</b>and<b>suseconds_t</b>types are defined as described in<i><a href="systypes.h.html"><sys/types.h></a></i>.<p>The<i><sys/time.h></i>header defines the<b>fd_set</b>type as a structure that includes at least the following member:<pre><code>long fds_bits[] bit mask for open file descriptions</code></pre><p>The<i><sys/time.h></i>header defines the following values for the <i>which</i> argument of<i><a href="getitimer.html">getitimer()</a></i>and<i><a href="setitimer.html">setitimer()</a></i>:<dl compact><dt>ITIMER_REAL<dd>Decrements in real time.<dt>ITIMER_VIRTUAL<dd>Decrements in process virtual time.<dt>ITIMER_PROF<dd>Decrements both in process virtual time and when the system is running onbehalf of the process.</dl><p>Each of the following may be declared as a function, or defined as amacro, or both:<dl compact><dt>void FD_CLR(int <i>fd</i>, fd_set *<i>fdset</i>)<dd>Clears the bit for the file descriptor <i>fd</i> in the file descriptor set<i>fdset</i>.<dt>int FD_ISSET(int <i>fd</i>, fd_set *<i>fdset</i>)<dd>Returns a non-zero value if the bit for the file descriptor <i>fd</i> isset in the file descriptor set by <i>fdset</i>, and 0 otherwise.<dt>void FD_SET(int <i>fd</i>, fd_set *<i>fdset</i>)<dd>Sets the bit for the file descriptor <i>fd</i> in the file descriptor set<i>fdset</i>.<dt>void FD_ZERO(fd_set *<i>fdset</i>)<dd>Initialises the file descriptor set <i>fdset</i> to have zero bits for all filedescriptors.<dt>FD_SETSIZE<dd>Maximum number of file descriptors in an <b>fd_set</b> structure.</dl><p>If implemented as macros, these may evaluate their arguments more thanonce, so that arguments must never be expressions with side effects.<p>The following are declared as functions and may also be defined as macros.Function prototypes must be provided for use with an ISO Ccompiler.<pre><code>int <a href="getitimer.html">getitimer</a>(int, struct itimerval *);int <a href="setitimer.html">setitimer</a>(int, const struct itimerval *, struct itimerval *);int <a href="gettimeofday.html">gettimeofday</a>(struct timeval *, void *);int <a href="select.html">select</a>(int, fd_set *, fd_set *, fd_set *, struct timeval *);int <a href="utimes.html">utimes</a>(const char *, const struct timeval [2]);</code></pre></blockquote><h4><a name = "tag_000_009_372"> </a>APPLICATION USAGE</h4><blockquote>None.</blockquote><h4><a name = "tag_000_009_373"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_009_374"> </a>SEE ALSO</h4><blockquote><i><a href="getitimer.html">getitimer()</a></i>,<i><a href="gettimeofday.html">gettimeofday()</a></i>,<i><a href="select.html">select()</a></i>,<i><a href="setitimer.html">setitimer()</a></i>,<i><a href="utimes.html">utimes()</a></i>.</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><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 + -