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28 .\" @(#)getitimer.2 8.3 (Berkeley) 5/16/95
29 .\" $FreeBSD: src/lib/libc/sys/getitimer.2,v 1.10.2.6 2001/12/14 18:34:00 ru Exp $
37 .Nd get/set value of interval timer
42 .Fd "#define ITIMER_REAL 0"
43 .Fd "#define ITIMER_VIRTUAL 1"
44 .Fd "#define ITIMER_PROF 2"
46 .Fn getitimer "int which" "struct itimerval *value"
48 .Fn setitimer "int which" "const struct itimerval *value" "struct itimerval *ovalue"
50 The system provides each process with three interval timers,
55 call returns the current value for the timer specified in
61 call sets a timer to the specified
63 (returning the previous value of the timer if
67 A timer value is defined by the
70 .Bd -literal -offset indent
72 struct timeval it_interval; /* timer interval */
73 struct timeval it_value; /* current value */
79 is non-zero, it indicates the time to the next timer expiration.
82 is non-zero, it specifies a value to be used in reloading
84 when the timer expires.
87 to 0 disables a timer, regardless of the value of
91 to 0 causes a timer to be disabled after its next expiration (assuming
95 Time values smaller than the resolution of the
96 system clock are rounded up to this resolution
97 (typically 10 milliseconds).
101 timer decrements in real time. A
104 delivered when this timer expires.
108 timer decrements in process virtual time.
109 It runs only when the process is executing. A
112 is delivered when it expires.
116 timer decrements both in process virtual time and
117 when the system is running on behalf of the process. It is designed
118 to be used by interpreters in statistically profiling the execution
119 of interpreted programs.
125 delivered. Because this signal may interrupt in-progress
126 system calls, programs using this timer must be prepared to
127 restart interrupted system calls.
129 The maximum number of seconds allowed for
137 Three macros for manipulating time values are defined in
140 sets a time value to zero,
142 tests if a time value is non-zero, and
144 compares two time values.
156 parameter specified a bad address.
160 parameter specified a time that was too large
171 function call appeared in