### 8.12 `ALARM` — Execute a routine after a given delay

Description:
  `ALARM(SECONDS, HANDLER [, STATUS])` causes external subroutine HANDLER to be executed after a delay of SECONDS by using `alarm(2)` to set up a signal and `signal(2)` to catch it. If STATUS is supplied, it will be returned with the number of seconds remaining until any previously scheduled alarm was due to be delivered, or zero if there was no previously scheduled alarm.
Standard:
  GNU extension
Class:
  Subroutine
Syntax:
  `CALL ALARM(SECONDS, HANDLER [, STATUS])`
Arguments:

  SECONDS | The type of the argument shall be a scalar `INTEGER`. It is `INTENT(IN)`.
  HANDLER | Signal handler (`INTEGER FUNCTION` or `SUBROUTINE`) or dummy/global `INTEGER` scalar. The scalar values may be either `SIG_IGN=1` to ignore the alarm generated or `SIG_DFL=0` to set the default action. It is `INTENT(IN)`.
  STATUS | (Optional) STATUS shall be a scalar variable of the default `INTEGER` kind. It is `INTENT(OUT)`.

Example:

                program test_alarm
                  external handler_print
                  integer i
                  call alarm (3, handler_print, i)
                  print *, i
                  call sleep(10)
                end program test_alarm

  This will cause the external routine handler_print to be called after 3 seconds.