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