opensolaris man page for alarm

alarm(2)							   System Calls 							  alarm(2)

NAME
       alarm - schedule an alarm signal

SYNOPSIS
       #include <unistd.h>

       unsigned int alarm(unsigned int seconds);

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. If seconds is greater than LONG_MAX/hz, seconds is rounded down to
       LONG_MAX/hz. The value of hz is normally 100.

       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(2) 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 5.11							    6 Jun 2007								  alarm(2)