PXFWAIT (L*X, M*X)

Module

USE IFPOSIX

CALL PXFWAIT (istat,iretpid,ierror)

If successful, ierror is set to zero; otherwise, an error code.

The PXFWAIT subroutine suspends execution of the current process until a child has exited, or until a signal is delivered whose action terminates the current process or calls a signal handling routine. If the child has already exited by the time of the call (a "zombie" process), a return is immediately made. Any system resources used by the child are freed.

The subroutine returns in iretpid the value of the process ID of the child that exited, or zero if no child was available. The returned value in istat can be used in subroutines IPXFWEXITSTATUS, IPXFWSTOPSIG, IPXFWTERMSIG, PXFWIFEXITED, PXFWIFSIGNALLED, and PXFWIFSTOPPED.

Example

program t1
use ifposix
integer(4) ipid, istat, ierror, ipid_ret, istat_ret
  print *," the child process will be born"
  call PXFFORK(IPID, IERROR)
  call PXFGETPID(IPID_RET,IERROR)
  if(IPID.EQ.0) then
     print *," I am a child process"
     print *," My child's pid is", IPID_RET
     call PXFGETPPID(IPID_RET,IERROR)
     print *," The pid of my parent is",IPID_RET
     print *," Now I have exited with code 0xABCD"
     call PXFEXIT(Z'ABCD')
  else
     print *," I am a parent process"
     print *," My parent pid is ", IPID_RET
     print *," I am creating the process with pid", IPID
     print *," Now I am waiting for the end of the child process"
     call PXFWAIT(ISTAT, IPID_RET, IERROR)
     print *," The child with pid ", IPID_RET," has exited"
     if( PXFWIFEXITED(ISTAT) ) then
       print *, " The child exited normally"
       istat_ret = IPXFWEXITSTATUS(ISTAT)
       print 10," The low byte of the child exit code is", istat_ret
     end if
  end if
10 FORMAT (A,Z)
end program