|
|
Send Fault Alarm SMS Every 30 Minutes
|
|
alarm(2) System Calls Manual alarm(2) NAME
alarm - set a process's alarm clock SYNOPSIS
DESCRIPTION
instructs the alarm clock of the calling process to send the signal to the calling process after the number of real-time seconds specified by sec have elapsed; see signal(5). Specific implementations might place limitations on the maximum supported alarm time. The constant defined in specifies the implementation-specific maximum. Whenever sec is greater that this maximum, it is silently rounded down to it. On all implementations, is guaranteed to be at least 31 days (in seconds). Alarm requests are not stacked; successive calls reset the alarm clock of the calling process. If sec is 0, any previously made alarm request is canceled. Alarms are not inherited by a child process across a but are inherited across an On systems that support the and system calls, the timer mechanism used by is the same as that used by Thus successive calls to and set and return the state of a single timer. In addition, sets the timer interval to zero. RETURN VALUE
returns the amount of time previously remaining in the alarm clock of the calling process. WARNINGS
In some implementations, error bounds for alarm are -1, +0 seconds (for the posting of the alarm, not the restart of the process). Thus a delay of 1 second can return immediately. The routine can be used to create a more precise delay. SEE ALSO
sleep(1), exec(2), getitimer(2), pause(2), signal(5), sleep(3C). STANDARDS CONFORMANCE
alarm(2)
