alarm(2)							   System Calls 							  alarm(2)

NAME

       alarm - schedule an alarm signal

SYNOPSIS

       #include <unistd.h>

       unsigned int alarm(unsigned int sec);

DESCRIPTION

       The alarm() function causes the system to generate a SIGALRM signal for the process after the number of real-time seconds specified by sec-
       onds  have  elapsed (see  signal.h(3HEAD)). 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 cancelled.

       Alarm requests are not stacked; only one SIGALRM  generation can  be  scheduled in this manner; if the SIGALRM signal has not yet been gen-
       erated, the call will result in rescheduling the time at which the SIGALRM signal will be generated.

       The fork(2) function clears pending alarms in the child process. A new process image created by one of the exec functions inherits the time
       left to an alarm signal in the old process's image.

RETURN VALUES

       If  there  is  a previous alarm request with time  remaining, alarm() returns  a  non-zero  value  that	is the number of seconds until the
       previous request would  have  generated	a SIGALRM signal.  Otherwise, alarm() returns 0.

ERRORS

       The alarm() function is always successful; no return value is reserved to indicate an error.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       exec(2), fork(2), signal.h(3HEAD), attributes(5), standards(5)

SunOS 5.10							    7 Jun 2001								  alarm(2)