Under very heavy loading, an ITIMER_REAL timer One instance of each of the signals listed above may be pendingįor a process. The generation and delivery of a signal are distinct, and only The new_value fields are zero that is, the timer is disabled.ĭon't use this Linux misfeature: it is nonportable and In Linux, this is treated as being equivalent to a call in which Many systems (Solaris, the BSDs, and perhaps others) treat this The standards are silent on the meaning of the call: Interfaces alarm(2), sleep(3), and usleep(3) unspecified. POSIX.1 leaves the interaction between setitimer() and the three (always true for ITIMER_VIRTUAL), the signal will be deliveredĪ child created via fork(2) does not inherit its parent's (But seeīUGS below.) If the timer expires while the process is active Timer resolution and on the system load see time(7). Timers will never expire before the requested time, but mayĮxpire some (short) time afterward, which depends on the system Recommending the use of the POSIX timers API ( timer_gettime(2), POSIX.1-2008 marks getitimer() and setitimer() obsolete, POSIX.1-2001, SVr4, 4.4BSD (this call first appeared in 4.2BSD). ITIMER_PROF or (since Linux 2.6.22) one of the tv_usecįields in the structure pointed to by new_value contains a On error, -1 is returned, andĮRRORS top EFAULT new_value, old_value, or curr_value is not valid aĮINVAL which is not one of ITIMER_REAL, ITIMER_VIRTUAL, or The timer if both of its subfields are zero, the timer is The new_interval field specifies the new interval for If bothįields in new_value are zero, then the timer is Is armed to initially expire at the specified time. If either field in new_value is nonzero, then the timer
Information that is returned by getitimer()). Return the previous value of the timer (i.e., the same If old_value is non-NULL, the buffer it points to is used to Which, by setting the timer to the value specified by new_value. The function setitimer() arms or disarms the timer specified by Single-shot timer (i.e., it expires just once). If both fields of it_interval are zero, then this is a The it_interval substructure is populated with the timer If both fields of it_valueĪre zero, then this timer is currently disarmed (inactive). Value changes as the timer counts down, and will be reset to Remaining until the next expiration of the specified timer. The it_value substructure is populated with the amount of time Specified by which in the buffer pointed to by curr_value. The function getitimer() places the current value of the timer Struct timeval it_value /* Time until next expiration */ Struct timeval it_interval /* Interval for periodic timer */ Timer values are defined by the following structures: To profile user and system CPU time consumed by theĪ process has only one of each of the three types of timers. In conjunction with ITIMER_VIRTUAL, this timer can be used The process.) At each expiration, a SIGPROF signal is Measurement includes CPU time consumed by all threads in This timer counts down against the total (i.e., both userĪnd system) CPU time consumed by the process. Time consumed by all threads in the process.) At eachĮxpiration, a SIGVTALRM signal is generated. This timer counts down against the user-mode CPU timeĬonsumed by the process. This timer counts down in real (i.e., wall clock) time.Īt each expiration, a SIGALRM signal is generated. Generates a different signal on timer expiration: Provided, each of which counts against a different clock and Three types of timers-specified via the which argument-are Timer is reset to the specified interval (if the interval is When a timerĮxpires, a signal is generated for the calling process, and the (optionally) at regular intervals after that. Timers that initially expire at some point in the future, and These system calls provide access to interval timers, that is, SYNOPSIS top #include int getitimer(int which, struct itimerval * curr_value ) int setitimer(int which, const struct itimerval *restrict new_value, struct itimerval *restrict old_value ) DESCRIPTION top Getitimer, setitimer - get or set value of an interval timer
#Itimter virtual itimer real manual#
GETITIMER(2) Linux Programmer's Manual GETITIMER(2) NAME top
0 kommentar(er)
