diff options
Diffstat (limited to 'man3p/getitimer.3p')
-rw-r--r-- | man3p/getitimer.3p | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/man3p/getitimer.3p b/man3p/getitimer.3p new file mode 100644 index 000000000..d1446f32a --- /dev/null +++ b/man3p/getitimer.3p @@ -0,0 +1,117 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "GETITIMER" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" getitimer +.SH NAME +getitimer, setitimer \- get and set value of interval timer +.SH SYNOPSIS +.LP +\fB#include <sys/time.h> +.br +.sp +int getitimer(int\fP \fIwhich\fP\fB, struct itimerval *\fP\fIvalue\fP\fB); +.br +int setitimer(int\fP \fIwhich\fP\fB, const struct itimerval *restrict\fP +\fIvalue\fP\fB, +.br +\ \ \ \ \ \ struct itimerval *restrict\fP \fIovalue\fP\fB); \fP +\fB +.br +\fP +.SH DESCRIPTION +.LP +The \fIgetitimer\fP() function shall store the current value of the +timer specified by \fIwhich\fP into the structure pointed +to by \fIvalue\fP. The \fIsetitimer\fP() function shall set the timer +specified by \fIwhich\fP to the value specified in the +structure pointed to by \fIvalue\fP, and if \fIovalue\fP is not a +null pointer, store the previous value of the timer in the +structure pointed to by \fIovalue\fP. +.LP +A timer value is defined by the \fBitimerval\fP structure, specified +in \fI<sys/time.h>\fP. If \fIit_value\fP is non-zero, it shall indicate +the time to the next +timer expiration. If \fIit_interval\fP is non-zero, it shall specify +a value to be used in reloading \fIit_value\fP when the +timer expires. Setting \fIit_value\fP to 0 shall disable a timer, +regardless of the value of \fIit_interval\fP. Setting +\fIit_interval\fP to 0 shall disable a timer after its next expiration +(assuming \fIit_value\fP is non-zero). +.LP +Implementations may place limitations on the granularity of timer +values. For each interval timer, if the requested timer value +requires a finer granularity than the implementation supports, the +actual timer value shall be rounded up to the next supported +value. +.LP +An XSI-conforming implementation provides each process with at least +three interval timers, which are indicated by the +\fIwhich\fP argument: +.TP 7 +ITIMER_REAL +Decrements in real time. A SIGALRM signal is delivered when this timer +expires. +.TP 7 +ITIMER_VIRTUAL +Decrements in process virtual time. It runs only when the process +is executing. A SIGVTALRM signal is delivered when it +expires. +.TP 7 +ITIMER_PROF +Decrements both in process virtual time and when the system is running +on behalf of the process. It is designed to be used by +interpreters in statistically profiling the execution of interpreted +programs. Each time the ITIMER_PROF timer expires, the SIGPROF +signal is delivered. +.sp +.LP +The interaction between \fIsetitimer\fP() and any of \fIalarm\fP(), +\fIsleep\fP(), or \fIusleep\fP() is unspecified. +.SH RETURN VALUE +.LP +Upon successful completion, \fIgetitimer\fP() or \fIsetitimer\fP() +shall return 0; otherwise, -1 shall be returned and +\fIerrno\fP set to indicate the error. +.SH ERRORS +.LP +The \fIsetitimer\fP() function shall fail if: +.TP 7 +.B EINVAL +The \fIvalue\fP argument is not in canonical form. (In canonical form, +the number of microseconds is a non-negative integer +less than 1000000 and the number of seconds is a non-negative integer.) +.sp +.LP +The \fIgetitimer\fP() and \fIsetitimer\fP() functions may fail if: +.TP 7 +.B EINVAL +The \fIwhich\fP argument is not recognized. +.sp +.LP +\fIThe following sections are informative.\fP +.SH EXAMPLES +.LP +None. +.SH APPLICATION USAGE +.LP +None. +.SH RATIONALE +.LP +None. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fIalarm\fP() , \fIsleep\fP() , \fItimer_getoverrun\fP() , \fIualarm\fP() +, \fIusleep\fP() , the Base Definitions volume of IEEE\ Std\ 1003.1-2001, +\fI<signal.h>\fP, \fI<sys/time.h>\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 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 . |