Three interfaces alarm(2), sleep(3), and usleep(3) POSIX.1 leaves the interaction between setitimer() and the ITIMER_VIRTUAL), the signal will be delivered immediately whenĪ child created via fork(2) does not inherit its parent's Timer expires while the process is active (always true for Some (short) time afterward, which depends on the system timer resolutionĪnd on the system load see time(7). Timers will never expire before the requested time, but may expire 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 value EINVAL which is not one of ITIMER_REAL, ITIMER_VIRTUAL, or ERRORS EFAULT new_value, old_value, or curr_value is not valid a On error, -1 is returned, andĮrrno is set to indicate the error. The new_interval field specifies the new intervalįor the timer if both of its subfields are zero, the timer is New_value are zero, then the timer is disarmed. Timer is armed to initially expire at the specified time. If either field in new_value is nonzero, then the Information that is returned by getitimer()). Is used to return the previous value of the timer (i.e., the same If old_value is non-NULL, the buffer it points to Specified by which, by setting the timer to the value specified by The function setitimer() arms or disarms the timer 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 This timer is currently disarmed (inactive). If both fields of it_value are zero, then This valueĬhanges as the timer counts down, and will be reset to it_interval Time remaining until the next expiration of the specified timer. The it_value substructure is populated with the amount of Timer specified by which in the buffer pointed to by The function getitimer() places the current value of the Struct timeval it_value /* Time until next expiration */ Struct timeval it_interval /* Interval for periodic timer */ Timer values are defined by the following structures: ![]() Profile user and system CPU time consumed by the process.Ī process has only one of each of the three types of timers. In conjunction with ITIMER_VIRTUAL, this timer can be used to (The measurement includes CPU time consumedīy all threads in the process.) At each expiration, a SIGPROF ![]() ITIMER_PROF This timer counts down against the total (i.e., both user and system) CPU Process.) At each expiration, a SIGVTALRM signal is generated. (The measurement includes CPU time consumed by all threads in the ITIMER_VIRTUAL This timer counts down against the user-mode CPU time consumed by the At eachĮxpiration, a SIGALRM signal is generated. Three types of timers-specified via the whichĪrgument-are provided, each of which counts against a different clockĪnd generates a different signal on timer expiration: ITIMER_REAL This timer counts down in real (i.e., wall clock) time. When a timer expires, a signal is generatedįor the calling process, and the timer is reset to the specified interval Timers that initially expire at some point in the future, and (optionally)Īt regular intervals after that. These system calls provide access to interval timers, that is, Standard C library ( libc, -lc) SYNOPSIS #include int getitimer(int which, struct itimerval * curr_value ) int setitimer(int which, const struct itimerval *restrict new_value, struct itimerval *_Nullable restrict old_value ) DESCRIPTION Getitimer, setitimer - get or set value of an interval timer LIBRARY
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |