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by Francesco Paolo Lovergine
rules: linking manpages-posix not manpages. |
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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved |
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by Francesco Paolo Lovergine
* Alligned to linux main manpages edition. |
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.TH "UALARM" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" |
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by Francesco Paolo Lovergine
rules: linking manpages-posix not manpages. |
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.\" ualarm |
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.SH NAME |
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ualarm \- set the interval timer
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.SH SYNOPSIS |
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.LP
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\fB#include <unistd.h>
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.br
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.sp
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useconds_t ualarm(useconds_t\fP \fIuseconds\fP\fB, useconds_t\fP \fIinterval\fP\fB); |
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\fP
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\fB
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.br
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\fP
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.SH DESCRIPTION |
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.LP
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The \fIualarm\fP() function shall cause the SIGALRM signal to be generated |
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for the calling process after the number of realtime |
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microseconds specified by the \fIuseconds\fP argument has elapsed. |
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When the \fIinterval\fP argument is non-zero, repeated timeout |
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notification occurs with a period in microseconds specified by the |
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\fIinterval\fP argument. If the notification signal, SIGALRM, |
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is not caught or ignored, the calling process is terminated. |
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.LP
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Implementations may place limitations on the granularity of timer |
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values. For each interval timer, if the requested timer value |
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requires a finer granularity than the implementation supports, the |
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actual timer value shall be rounded up to the next supported |
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value. |
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.LP
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Interactions between \fIualarm\fP() and any of the following are unspecified: |
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.sp
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.RS
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.nf
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\fIalarm\fP() |
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\fInanosleep\fP() |
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\fIsetitimer\fP() |
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\fItimer_create\fP() |
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\fItimer_delete\fP() |
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\fItimer_getoverrun\fP() |
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\fItimer_gettime\fP() |
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\fItimer_settime\fP() |
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\fIsleep\fP() |
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.fi
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.RE
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.SH RETURN VALUE |
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.LP
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The \fIualarm\fP() function shall return the number of microseconds |
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remaining from the previous \fIualarm\fP() call. If no |
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timeouts are pending or if \fIualarm\fP() has not previously been |
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called, \fIualarm\fP() shall return 0. |
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.SH ERRORS |
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.LP
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No errors are defined. |
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.LP
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\fIThe following sections are informative.\fP |
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.SH EXAMPLES |
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.LP
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None. |
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.SH APPLICATION USAGE |
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.LP
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Applications are recommended to use \fInanosleep\fP() if the Timers |
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option is |
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supported, or \fIsetitimer\fP(), \fItimer_create\fP(), \fItimer_delete\fP(), |
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\fItimer_getoverrun\fP(), \fItimer_gettime\fP(), or \fItimer_settime\fP() |
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instead of this function. |
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.SH RATIONALE |
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.LP
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None. |
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.SH FUTURE DIRECTIONS |
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.LP
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None. |
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.SH SEE ALSO |
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.LP
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\fIalarm\fP() , \fInanosleep\fP() , \fIsetitimer\fP() , \fIsleep\fP() |
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, \fItimer_create\fP() , \fItimer_delete\fP() , \fItimer_getoverrun\fP() |
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, the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<unistd.h>\fP |
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.SH COPYRIGHT |
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Portions of this text are reprinted and reproduced in electronic form |
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology |
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-- Portable Operating System Interface (POSIX), The Open Group Base |
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of |
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Electrical and Electronics Engineers, Inc and The Open Group. In the |
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event of any discrepancy between this version and the original IEEE and |
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The Open Group Standard, the original IEEE and The Open Group Standard |
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is the referee document. The original Standard can be obtained online at |
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http://www.opengroup.org/unix/online.html . |