ALARM(2,L) AIX Technical Reference ALARM(2,L) ------------------------------------------------------------------------------- alarm PURPOSE Sets a process's alarm clock. SYNTAX unsigned int alarm (secs) unsigned int secs; DESCRIPTION The alarm subroutine sets a timer which causes a SIGALRM signal to be delivered to the calling process after the number of real-time seconds specified by the secs parameter have elapsed. After the SIGALRM signal is delivered the timer is turned off. Unless caught, blocked, or ignored the SIGALRM signal will cause the process to terminate. (See "sigaction, sigvec, signal" for more information about signals.) Alarm requests are not stacked; successive calls reset the alarm timer. If the secs parameter is 0 the alarm timer is turned off, cancelling any pending alarm request. Because of process scheduling delays, the actual time lapse between setting the timer and getting the SIGALRM signal may be more than requested. The alarm timer value is inherited through the exec system call. The child process after a fork system call will have its alarm timer turned off. If the Transparent Computing Facility is installed, the alarm timer is preserved through migrate and rexec system calls and during migrates caused by SIGMIGRATE. The alarm subroutine is a simplified interface to the setitimer system call. See "getitimer, setitimer" for more information. RETURN VALUE The alarm subroutine returns the number of seconds previously remaining on the alarm timer, or 0 if the timer was not running. (Note that because timer values are inherited through exec, the timer may already be running when a program begins to execute.) RELATED INFORMATION Processed November 7, 1990 ALARM(2,L) 1
ALARM(3,L) AIX Technical Reference ALARM(3,L) In this book: "exec: execl, execv, execle, execve, execlp, execvp," "getitimer, setitimer," "pause," and "sigaction, sigvec, signal" . Processed November 7, 1990 ALARM(3,L) 2