ALARM(3) BSD Programmer's Manual ALARM(3)NAMEalarm - set signal timer alarmSYNOPSIS
#include <unistd.h>
unsigned int
alarm(unsigned int seconds);
DESCRIPTION
This interface is made obsolete by setitimer(2).
The alarm() function waits a count of seconds before asserting the ter-
minating signal SIGALRM. When the signal has successfully been caught,
alarm() returns the amount of time left on the clock. The maximum number
of seconds allowed is 100000000.
If an alarm has been set with alarm(), another call to alarm() will su-
persede the prior call. The request alarm(0) voids the current alarm.
RETURN VALUES
If the call succeeds, any time left remaining from a previous call is re-
turned. If an error occurs, the value -1 is returned, and a more precise
error code is placed in the global variable errno.
SEE ALSOsetitimer(2), sigaction(2), signal(3), sigpause(3), sigvec(3), sleep(3),
ualarm(3), usleep(3)STANDARDS
The alarm() function conforms to IEEE Std 1003.1-1990 ("POSIX").
HISTORY
An alarm() function appeared in Version 7 AT&T UNIX.
MirOS BSD #10-current April 19, 1994 1