diff options
Diffstat (limited to 'man2/getitimer.2')
| -rw-r--r-- | man2/getitimer.2 | 34 |
1 files changed, 17 insertions, 17 deletions
diff --git a/man2/getitimer.2 b/man2/getitimer.2 index 08f6d0d348..1d7d6ca632 100644 --- a/man2/getitimer.2 +++ b/man2/getitimer.2 @@ -29,7 +29,7 @@ and (optionally) at regular intervals after that. When a timer expires, a signal is generated for the calling process, and the timer is reset to the specified interval (if the interval is nonzero). - +.PP Three types of timers\(emspecified via the .IR which argument\(emare provided, @@ -56,14 +56,14 @@ CPU time consumed by the process. At each expiration, a .B SIGPROF signal is generated. - +.IP In conjunction with .BR ITIMER_VIRTUAL , this timer can be used to profile user and system CPU time consumed by the process. .LP A process has only one of each of the three types of timers. - +.PP Timer values are defined by the following structures: .PD 0 .in +4n @@ -88,7 +88,7 @@ places the current value of the timer specified by .IR which in the buffer pointed to by .IR curr_value . - +.PP The .IR it_value substructure is populated with the amount of time remaining until @@ -99,7 +99,7 @@ when the timer expires. If both fields of .IR it_value are zero, then this timer is currently disarmed (inactive). - +.PP The .IR it_interval substructure is populated with the timer interval. @@ -119,7 +119,7 @@ is non-NULL, the buffer it points to is used to return the previous value of the timer (i.e., the same information that is returned by .BR getitimer ()). - +.PP If either field in .IR new_value.it_value is nonzero, @@ -127,7 +127,7 @@ then the timer is armed to initially expire at the specified time. If both fields in .IR new_value.it_value are zero, then the timer is disarmed. - +.PP The .IR new_value.it_interval field specifies the new interval for the timer; @@ -177,13 +177,13 @@ on the system timer resolution and on the system load; see If the timer expires while the process is active (always true for .BR ITIMER_VIRTUAL ), the signal will be delivered immediately when generated. - +.PP A child created via .BR fork (2) does not inherit its parent's interval timers. Interval timers are preserved across an .BR execve (2). - +.PP POSIX.1 leaves the interaction between .BR setitimer () @@ -193,16 +193,16 @@ and the three interfaces and .BR usleep (3) unspecified. - +.PP The standards are silent on the meaning of the call: - +.PP setitimer(which, NULL, &old_value); - +.PP Many systems (Solaris, the BSDs, and perhaps others) treat this as equivalent to: - +.PP getitimer(which, &old_value); - +.PP In Linux, this is treated as being equivalent to a call in which the .I new_value fields are zero; that is, the timer is disabled. @@ -217,7 +217,7 @@ Under very heavy loading, an timer may expire before the signal from a previous expiration has been delivered. The second signal in such an event will be lost. - +.PP On Linux kernels before 2.6.16, timer values are represented in jiffies. If a request is made set a timer with a value whose jiffies representation exceeds @@ -232,14 +232,14 @@ approximately 99.42 days. Since Linux 2.6.16, the kernel uses a different internal representation for times, and this ceiling is removed. - +.PP On certain systems (including i386), Linux kernels before version 2.6.12 have a bug which will produce premature timer expirations of up to one jiffy under some circumstances. This bug is fixed in kernel 2.6.12. .\" 4 Jul 2005: It looks like this bug may remain in 2.4.x. .\" http://lkml.org/lkml/2005/7/1/165 - +.PP POSIX.1-2001 says that .BR setitimer () should fail if a |