Manual Pages for UNIX Operating System command usage for man alarm

System Calls                                             alarm(2)



NAME
     alarm - schedule an alarm signal

SYNOPSIS
     #include 

     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 seconds  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  can-
     celled.  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 generated, 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 pro-
     cess.  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  attri-
     butes:








SunOS 5.11           Last change: 6 Jun 2007                    1






System Calls                                             alarm(2)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | Async-Signal-Safe           |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     exec(2),  fork(2),  signal.h(3HEAD),  attributes(5),   stan-
     dards(5)









































SunOS 5.11           Last change: 6 Jun 2007                    2