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diff --git a/upstream/mageia-cauldron/man3p/timer_getoverrun.3p b/upstream/mageia-cauldron/man3p/timer_getoverrun.3p new file mode 100644 index 00000000..d243b6b9 --- /dev/null +++ b/upstream/mageia-cauldron/man3p/timer_getoverrun.3p @@ -0,0 +1,275 @@ +'\" et +.TH TIMER_GETOVERRUN "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.\" +.SH NAME +timer_getoverrun, +timer_gettime, +timer_settime +\(em per-process timers +.SH SYNOPSIS +.LP +.nf +#include <time.h> +.P +int timer_getoverrun(timer_t \fItimerid\fP); +int timer_gettime(timer_t \fItimerid\fP, struct itimerspec *\fIvalue\fP); +int timer_settime(timer_t \fItimerid\fP, int \fIflags\fP, + const struct itimerspec *restrict \fIvalue\fP, + struct itimerspec *restrict \fIovalue\fP); +.fi +.SH DESCRIPTION +The +\fItimer_gettime\fR() +function shall store the amount of time until the specified timer, +.IR timerid , +expires and the reload value of the timer into the space pointed to by +the +.IR value +argument. The +.IR it_value +member of this structure shall contain the amount of time before the timer +expires, or zero if the timer is disarmed. This value is returned as +the interval until timer expiration, even if the timer was armed with +absolute time. The +.IR it_interval +member of +.IR value +shall contain the reload value last set by +\fItimer_settime\fR(). +.P +The +\fItimer_settime\fR() +function shall set the time until the next expiration of the timer +specified by +.IR timerid +from the +.IR it_value +member of the +.IR value +argument and arm the timer if the +.IR it_value +member of +.IR value +is non-zero. If the specified timer was already armed when +\fItimer_settime\fR() +is called, this call shall reset the time until next expiration to the +.IR value +specified. If the +.IR it_value +member of +.IR value +is zero, the timer shall be disarmed. The effect of disarming or +resetting a timer with pending expiration notifications is unspecified. +.P +If the flag TIMER_ABSTIME is not set in the argument +.IR flags , +\fItimer_settime\fR() +shall behave as if the time until next expiration is set to be equal +to the interval specified by the +.IR it_value +member of +.IR value . +That is, the timer shall expire in +.IR it_value +nanoseconds from when the call is made. If the flag TIMER_ABSTIME is +set in the argument +.IR flags , +\fItimer_settime\fR() +shall behave as if the time until next expiration is set to be equal +to the difference between the absolute time specified by the +.IR it_value +member of +.IR value +and the current value of the clock associated with +.IR timerid . +That is, the timer shall expire when the clock reaches the value +specified by the +.IR it_value +member of +.IR value . +If the specified time has already passed, the function shall succeed +and the expiration notification shall be made. +.P +The reload value of the timer shall be set to the value specified by the +.IR it_interval +member of +.IR value . +When a timer is armed with a non-zero +.IR it_interval , +a periodic (or repetitive) timer is specified. +.P +Time values that are between two consecutive non-negative integer +multiples of the resolution of the specified timer shall be rounded up +to the larger multiple of the resolution. Quantization error shall not +cause the timer to expire earlier than the rounded time value. +.P +If the argument +.IR ovalue +is not NULL, the +\fItimer_settime\fR() +function shall store, in the location referenced by +.IR ovalue , +a value representing the previous amount of time before the timer would +have expired, or zero if the timer was disarmed, together with the +previous timer reload value. Timers shall not expire before their +scheduled time. +.P +Only a single signal shall be queued to the process for a given timer +at any point in time. When a timer for which a signal is still pending +expires, no signal shall be queued, and a timer overrun shall occur. +When a timer expiration signal is delivered to or accepted by a +process, the +\fItimer_getoverrun\fR() +function shall return the timer expiration overrun count for the +specified timer. The overrun count returned contains the number of +extra timer expirations that occurred between the time the signal was +generated (queued) and when it was delivered or accepted, up to but not +including an implementation-defined maximum of +{DELAYTIMER_MAX}. +If the number of such extra expirations is greater than or equal to +{DELAYTIMER_MAX}, +then the overrun count shall be set to +{DELAYTIMER_MAX}. +The value returned by +\fItimer_getoverrun\fR() +shall apply to the most recent expiration signal delivery or acceptance +for the timer. If no expiration signal has been delivered for the timer, +the return value of +\fItimer_getoverrun\fR() +is unspecified. +.P +The behavior is undefined if the value specified by the +.IR timerid +argument to +\fItimer_getoverrun\fR(), +\fItimer_gettime\fR(), +or +\fItimer_settime\fR() +does not correspond to a timer ID returned by +\fItimer_create\fR() +but not yet deleted by +\fItimer_delete\fR(). +.SH "RETURN VALUE" +If the +\fItimer_getoverrun\fR() +function succeeds, it shall return the timer expiration overrun count +as explained above. +.P +If the +\fItimer_gettime\fR() +or +\fItimer_settime\fR() +functions succeed, a value of 0 shall be returned. +.P +If an error occurs for any of these functions, the value \-1 shall be +returned, and +.IR errno +set to indicate the error. +.SH ERRORS +The +\fItimer_settime\fR() +function shall fail if: +.TP +.BR EINVAL +A +.IR value +structure specified a nanosecond value less than zero or greater than +or equal to 1\|000 million, and the +.IR it_value +member of that structure did not specify zero seconds and nanoseconds. +.P +The +\fItimer_settime\fR() +function may fail if: +.TP +.BR EINVAL +The +.IR it_interval +member of +.IR value +is not zero and the timer was created with notification by creation of +a new thread (\c +.IR sigev_sigev_notify +was SIGEV_THREAD) and a fixed stack address has been set in the thread +attribute pointed to by +.IR sigev_notify_attributes . +.LP +.IR "The following sections are informative." +.SH EXAMPLES +None. +.SH "APPLICATION USAGE" +Using fixed stack addresses is problematic when timer expiration is +signaled by the creation of a new thread. Since it cannot be assumed +that the thread created for one expiration is finished before the next +expiration of the timer, it could happen that two threads use the same +memory as a stack at the same time. This is invalid and produces +undefined results. +.SH RATIONALE +Practical clocks tick at a finite rate, with rates of 100 hertz and +1\|000 hertz being common. The inverse of this tick rate is the clock +resolution, also called the clock granularity, which in either case is +expressed as a time duration, being 10 milliseconds and 1 millisecond +respectively for these common rates. The granularity of practical +clocks implies that if one reads a given clock twice in rapid +succession, one may get the same time value twice; and that timers must +wait for the next clock tick after the theoretical expiration time, to +ensure that a timer never returns too soon. Note also that the +granularity of the clock may be significantly coarser than the +resolution of the data format used to set and get time and interval +values. Also note that some implementations may choose to adjust time +and/or interval values to exactly match the ticks of the underlying +clock. +.P +This volume of POSIX.1\(hy2017 defines functions that allow an application to determine +the implementation-supported resolution for the clocks and requires an +implementation to document the resolution supported for timers and +\fInanosleep\fR() +if they differ from the supported clock resolution. This is more of a +procurement issue than a runtime application issue. +.P +If an implementation detects that the value specified by the +.IR timerid +argument to +\fItimer_getoverrun\fR(), +\fItimer_gettime\fR(), +or +\fItimer_settime\fR() +does not correspond to a timer ID returned by +\fItimer_create\fR() +but not yet deleted by +\fItimer_delete\fR(), +it is recommended that the function should fail and report an +.BR [EINVAL] +error. +.SH "FUTURE DIRECTIONS" +None. +.SH "SEE ALSO" +.IR "\fIclock_getres\fR\^(\|)", +.IR "\fItimer_create\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2017, +.IR "\fB<time.h>\fP" +.\" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1-2017, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, 2018 Edition, +Copyright (C) 2018 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +In the event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . +.PP +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |