diff options
Diffstat (limited to 'man2/getitimer.2')
| -rw-r--r-- | man2/getitimer.2 | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/man2/getitimer.2 b/man2/getitimer.2 index 422a04e..6674117 100644 --- a/man2/getitimer.2 +++ b/man2/getitimer.2 @@ -10,7 +10,7 @@ .\" 2005-04-06 mtk, Matthias Lang <matthias@corelatus.se> .\" Noted MAX_SEC_IN_JIFFIES ceiling .\" -.TH getitimer 2 2023-05-03 "Linux man-pages 6.05.01" +.TH getitimer 2 2023-10-31 "Linux man-pages 6.7" .SH NAME getitimer, setitimer \- get or set value of an interval timer .SH LIBRARY @@ -19,7 +19,7 @@ Standard C library .SH SYNOPSIS .nf .B #include <sys/time.h> -.PP +.P .BI "int getitimer(int " which ", struct itimerval *" curr_value ); .BI "int setitimer(int " which ", const struct itimerval *restrict " new_value , .BI " struct itimerval *_Nullable restrict " old_value ); @@ -31,7 +31,7 @@ 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 +.P Three types of timers\[em]specified via the .I which argument\[em]are provided, @@ -63,11 +63,11 @@ In conjunction with .BR ITIMER_VIRTUAL , this timer can be used to profile user and system CPU time consumed by the process. -.PP +.P A process has only one of each of the three types of timers. -.PP +.P Timer values are defined by the following structures: -.PP +.P .in +4n .EX struct itimerval { @@ -89,7 +89,7 @@ places the current value of the timer specified by .I which in the buffer pointed to by .IR curr_value . -.PP +.P The .I it_value substructure is populated with the amount of time remaining until @@ -100,7 +100,7 @@ when the timer expires. If both fields of .I it_value are zero, then this timer is currently disarmed (inactive). -.PP +.P The .I it_interval substructure is populated with the timer interval. @@ -120,7 +120,7 @@ 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 +.P If either field in .I new_value.it_value is nonzero, @@ -128,7 +128,7 @@ then the timer is armed to initially expire at the specified time. If both fields in .I new_value.it_value are zero, then the timer is disarmed. -.PP +.P The .I new_value.it_interval field specifies the new interval for the timer; @@ -161,22 +161,22 @@ fields in the structure pointed to by contains a value outside the range [0, 999999]. .SH VERSIONS The standards are silent on the meaning of the call: -.PP +.P .in +4n .EX setitimer(which, NULL, &old_value); .EE .in -.PP +.P Many systems (Solaris, the BSDs, and perhaps others) treat this as equivalent to: -.PP +.P .in +4n .EX getitimer(which, &old_value); .EE .in -.PP +.P 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. @@ -203,13 +203,13 @@ 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 +.P 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 +.P POSIX.1 leaves the interaction between .BR setitimer () @@ -228,7 +228,7 @@ 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 +.P Before Linux 2.6.16, timer values are represented in jiffies. If a request is made set a timer with a value whose jiffies representation exceeds @@ -243,14 +243,14 @@ approximately 99.42 days. Since Linux 2.6.16, the kernel uses a different internal representation for times, and this ceiling is removed. -.PP +.P On certain systems (including i386), Linux kernels before Linux 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 Linux 2.6.12. .\" 4 Jul 2005: It looks like this bug may remain in Linux 2.4.x. .\" http://lkml.org/lkml/2005/7/1/165 -.PP +.P POSIX.1-2001 says that .BR setitimer () should fail if a |