timerlib.html

Vxworks API操作系统和驱动程序设计API。压缩的HTML文件

Both values are copied to the <i>value</i> structure.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
0 (OK), or -1 (ERROR) if <i>timerid</i> is invalid.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./timerLib.html#top">timerLib</a></b>

<hr>
<a name="timer_getoverrun"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>timer_getoverrun(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>timer_getoverrun(&nbsp;)</strong> - return the timer expiration overrun (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int timer_getoverrun
    (
    timer_t timerid           /* timer ID */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine returns the timer expiration overrun count for <i>timerid</i>,
when called from a timer expiration signal catcher.  The overrun count is
the number of extra timer expirations that have occurred, up to the
implementation-defined maximum <b>_POSIX_DELAYTIMER_MAX</b>.  If the count is
greater than the maximum, it returns the maximum.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
<p>
The number of overruns, or <b>_POSIX_DELAYTIMER_MAX</b> if the count equals or is
greater than <b>_POSIX_DELAYTIMER_MAX</b>, or -1 (ERROR) if <i>timerid</i> is invalid.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL, ENOSYS
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./timerLib.html#top">timerLib</a></b>

<hr>
<a name="timer_settime"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>timer_settime(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>timer_settime(&nbsp;)</strong> - set the time until the next expiration and arm timer (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int timer_settime
    (
    timer_t                   timerid, /* timer ID */
    int                       flags,   /* absolute or relative */
    const struct itimerspec * value,   /* time to be set */
    struct itimerspec *       ovalue   /* previous time set (NULL=no result) */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine sets the next expiration of the timer, using the <b>.it_value</b>
of <i>value</i>, thus arming the timer.  If the timer is already armed, this
call resets the time until the next expiration.  If <b>.it_value</b> is zero,
the timer is disarmed.
<p>
If <i>flags</i> is not equal to <b>TIMER_ABSTIME</b>, the interval is relative to the
current time, the interval being the <b>.it_value</b> of the <i>value</i> parameter.
If <i>flags</i> is equal to <b>TIMER_ABSTIME</b>, the expiration is set to
the difference between the absolute time of <b>.it_value</b> and the current
value of the clock associated with <i>timerid</i>.  If the time has already
passed, then the timer expiration notification is made immediately.
The task that sets the timer receives the signal; in other words, the taskId
is noted.  If a timer is set by an ISR, the signal is delivered to the
task that created the timer.
<p>
The reload value of the timer is set to the value specified by
the <b>.it_interval</b> field of <i>value</i>.  When a timer is
armed with a nonzero <b>.it_interval</b> a periodic timer is set up.
<p>
Time values that are between two consecutive non-negative integer
multiples of the resolution of the specified timer are rounded up to
the larger multiple of the resolution.
<p>
If <i>ovalue</i> is non-NULL, the routine stores a value representing the
previous amount of time before the timer would have expired.  Or if the
timer is disarmed, the routine stores zero, together with the previous
timer reload value.  The <i>ovalue</i> parameter is the same value as that 
returned by <b><a href="./timerLib.html#timer_gettime">timer_gettime</a>(&nbsp;)</b> and is subject to the timer resolution.
<p>
</blockquote><h4>WARNING</h4><blockquote><p>
If <b><a href="./clockLib.html#clock_settime">clock_settime</a>(&nbsp;)</b> is called to reset the absolute clock time after a timer
has been set with <b><a href="./timerLib.html#timer_settime">timer_settime</a>(&nbsp;)</b>, and if <i>flags</i> is equal to <b>TIMER_ABSTIME</b>, 
then the timer will behave unpredictably.  If you must reset the absolute
clock time after setting a timer, do not use <i>flags</i> equal to <b>TIMER_ABSTIME</b>.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
<p>
0 (OK), or -1 (ERROR) if <i>timerid</i> is invalid, the number of nanoseconds 
specified by <i>value</i> is less than 0 or greater than or equal to 
1,000,000,000, or the time specified by <i>value</i> exceeds the maximum 
allowed by the timer.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./timerLib.html#top">timerLib</a></b>

<hr>
<a name="nanosleep"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>nanosleep(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>nanosleep(&nbsp;)</strong> - suspend the current task until the time interval elapses (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int nanosleep
    (
    const struct timespec * rqtp, /* time to delay */
    struct timespec *       rmtp  /* premature wakeup (NULL=no result) */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine suspends the current task for a specified time <i>rqtp</i>
or until a signal or event notification is made.
<p>
The suspension may be longer than requested due to the rounding up of the
request to the timer's resolution or to other scheduling activities (e.g.,
a higher priority task intervenes).
<p>
The <b>timespec</b> structure is defined as follows:
<p>
<pre>struct timespec
    {
                               /* interval = tv_sec*10**9 + tv_nsec */
     time_t tv_sec;            /* seconds */
     long tv_nsec;             /* nanoseconds (0 - 1,000,000,000) */
     };
</pre>

If <i>rmtp</i> is non-NULL, the <b>timespec</b> structure is updated to contain the
amount of time remaining.  If <i>rmtp</i> is NULL, the remaining time is not
returned.  The <i>rqtp</i> parameter is greater than 0 or less than or equal to
1,000,000,000.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
<p>
0 (OK), or -1 (ERROR) if the routine is interrupted by a signal or an 
asynchronous event notification, or <i>rqtp</i> is invalid.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL, EINTR
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./timerLib.html#top">timerLib</a></b>, <b><a href="./timerLib.html#sleep">sleep</a>(&nbsp;)</b>, <b><a href="./taskLib.html#taskDelay">taskDelay</a>(&nbsp;)</b>

<hr>
<a name="sleep"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>sleep(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>sleep(&nbsp;)</strong> - delay for a specified amount of time</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>unsigned int sleep
    (
    unsigned int secs
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine causes the calling task to be blocked for <i>secs</i> seconds.
<p>
The time the task is blocked for may be longer than requested due to the
rounding up of the request to the timer's resolution or to other scheduling
activities (e.g., a higher priority task intervenes).
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
Zero if the requested time has elapsed, or the number of seconds
remaining if it was interrupted.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL, EINTR
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./timerLib.html#top">timerLib</a></b>, <b><a href="./timerLib.html#nanosleep">nanosleep</a>(&nbsp;)</b>, <b><a href="./taskLib.html#taskDelay">taskDelay</a>(&nbsp;)</b>

<hr>
<a name="alarm"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>alarm(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>alarm(&nbsp;)</strong> - set an alarm clock for delivery of a signal</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>unsigned int alarm
    (
    unsigned int secs
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine arranges for a <b>SIGALRM</b> signal to be delivered to the
calling task after <i>secs</i> seconds.
<p>
If <i>secs</i> is zero, no new alarm is scheduled. In all cases, any previously
set alarm is cancelled.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
Time remaining until a previously scheduled alarm was due to be
delivered, zero if there was no previous alarm, or ERROR in case of an
error.
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./timerLib.html#top">timerLib</a></b>

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