alarm
Synopsis
#include <unistd.h>
unsigned alarm(unsigned seconds);
Status
Partially implemented
Conformance
IEEE Std 1003.1-2017
Description
The purpose is to schedule an alarm signal. The alarm() function shall cause the system to generate a SIGALRM signal
for the process after the number of real-time
seconds specified by seconds have elapsed. Processor scheduling delays may prevent the process from handling the
signal as soon as it is generated.
If seconds is 0, a pending alarm request, if any, is canceled.
Alarm requests are not stacked, only one SIGALRM generation can be scheduled in this manner. If the SIGALRM signal
has not yet been generated, the call shall result in rescheduling the time at which the SIGALRM signal is generated.
Interactions between alarm() and setitimer() are unspecified.
Return value
If there is a previous alarm() request with time remaining, alarm() shall return a non-zero value that is the number
of seconds until the previous request would have generated a SIGALRM signal. Otherwise, alarm() shall return 0.
Errors
The alarm() function is always successful, and no return value is reserved to indicate an error.
Tests
Untested
Known bugs
None