Return to getitimer.2 CVS log

Up to [CSRG BSD Unix] / 43BSDReno / lib / libc / sys

Annotation of 43BSDReno/lib/libc/sys/getitimer.2, revision 1.1

1.1     ! root        1: .\" Copyright (c) 1983 The Regents of the University of California.
        !             2: .\" All rights reserved.
        !             3: .\"
        !             4: .\" Redistribution and use in source and binary forms are permitted provided
        !             5: .\" that: (1) source distributions retain this entire copyright notice and
        !             6: .\" comment, and (2) distributions including binaries display the following
        !             7: .\" acknowledgement:  ``This product includes software developed by the
        !             8: .\" University of California, Berkeley and its contributors'' in the
        !             9: .\" documentation or other materials provided with the distribution and in
        !            10: .\" all advertising materials mentioning features or use of this software.
        !            11: .\" Neither the name of the University nor the names of its contributors may
        !            12: .\" be used to endorse or promote products derived from this software without
        !            13: .\" specific prior written permission.
        !            14: .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            15: .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            16: .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            17: .\"
        !            18: .\"    @(#)getitimer.2 6.5 (Berkeley) 6/23/90
        !            19: .\"
        !            20: .TH GETITIMER 2 "June 23, 1990"
        !            21: .UC 5
        !            22: .SH NAME
        !            23: getitimer, setitimer \- get/set value of interval timer
        !            24: .SH SYNOPSIS
        !            25: .nf
        !            26: .ft B
        !            27: #include <sys/time.h>
        !            28: .PP
        !            29: .ft B
        !            30: #define ITIMER_REAL    0       /* real time intervals */
        !            31: #define ITIMER_VIRTUAL 1       /* virtual time intervals */
        !            32: #define ITIMER_PROF    2       /* user and system virtual time */
        !            33: .sp
        !            34: .ft B
        !            35: getitimer(which, value)
        !            36: int which;
        !            37: struct itimerval *value;
        !            38: .PP
        !            39: .ft B
        !            40: setitimer(which, value, ovalue)
        !            41: int which;
        !            42: struct itimerval *value, *ovalue;
        !            43: .fi
        !            44: .SH DESCRIPTION
        !            45: The system provides each process with three interval timers,
        !            46: defined in
        !            47: .RI < sys/time.h >.
        !            48: The
        !            49: .I getitimer
        !            50: call returns the current value for the timer specified in
        !            51: .I which
        !            52: in the structure at
        !            53: .IR value .
        !            54: The
        !            55: .I setitimer
        !            56: call sets a timer to the specified
        !            57: .I value
        !            58: (returning the previous value of the timer if
        !            59: .I ovalue
        !            60: is nonzero).
        !            61: .PP
        !            62: A timer value is defined by the 
        !            63: .I itimerval
        !            64: structure:
        !            65: .PP
        !            66: .nf
        !            67: .RS
        !            68: .DT
        !            69: struct itimerval {
        !            70:        struct  timeval it_interval;    /* timer interval */
        !            71:        struct  timeval it_value;       /* current value */
        !            72: };
        !            73: .RE
        !            74: .fi
        !            75: .PP
        !            76: If
        !            77: .I it_value
        !            78: is non-zero, it indicates the time to the next timer expiration. 
        !            79: If
        !            80: .I it_interval
        !            81: is non-zero, it specifies a value to be used in reloading 
        !            82: .I it_value
        !            83: when the timer expires.
        !            84: Setting 
        !            85: .I it_value
        !            86: to 0 disables a timer.  Setting 
        !            87: .I it_interval
        !            88: to 0 causes a timer to be disabled after its next expiration (assuming
        !            89: .I it_value
        !            90: is non-zero).
        !            91: .PP
        !            92: Time values smaller than the resolution of the
        !            93: system clock are rounded up to this resolution
        !            94: (on the VAX, 10 milliseconds).
        !            95: .PP
        !            96: The ITIMER_REAL timer decrements in real time.  A SIGALRM signal is
        !            97: delivered when this timer expires.
        !            98: .PP
        !            99: The ITIMER_VIRTUAL timer decrements in process virtual time.
        !           100: It runs only when the process is executing.  A SIGVTALRM signal
        !           101: is delivered when it expires.
        !           102: .PP
        !           103: The ITIMER_PROF timer decrements both in process virtual time and
        !           104: when the system is running on behalf of the process.  It is designed
        !           105: to be used by interpreters in statistically profiling the execution
        !           106: of interpreted programs.
        !           107: Each time the ITIMER_PROF timer expires, the SIGPROF signal is
        !           108: delivered.  Because this signal may interrupt in-progress
        !           109: system calls, programs using this timer must be prepared to
        !           110: restart interrupted system calls.
        !           111: .SH NOTES
        !           112: Three macros for manipulating time values are defined in
        !           113: .RI < sys/time.h >.
        !           114: .I Timerclear
        !           115: sets a time value to zero,
        !           116: .I timerisset
        !           117: tests if a time value is non-zero, and
        !           118: .I timercmp
        !           119: compares two time values (beware that >= and <= do not
        !           120: work with this macro).
        !           121: .SH "RETURN VALUE
        !           122: If the calls succeed, a value of 0 is returned.  If an error occurs,
        !           123: the value \-1 is returned, and a more precise error code is placed
        !           124: in the global variable \fIerrno\fP.
        !           125: .SH "ERRORS
        !           126: The possible errors are:
        !           127: .TP 15
        !           128: [EFAULT]
        !           129: The \fIvalue\fP parameter specified a bad address.
        !           130: .TP 15
        !           131: [EINVAL]
        !           132: A \fIvalue\fP parameter specified a time was too large
        !           133: to be handled.
        !           134: .SH "SEE ALSO"
        !           135: select(2), sigvec(2), gettimeofday(2)

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.