C -*- Mode: Fortran; -*- 

C

C  (C) 2003 by Argonne National Laboratory.

C      See COPYRIGHT in top-level directory.

C

      subroutine query_fn( extrastate, status, ierr )

      implicit none

      include 'mpif.h'

      integer status(MPI_STATUS_SIZE), ierr

      include 'attr1aints.h'

C

C    set a default status

      status(MPI_SOURCE) = MPI_UNDEFINED

      status(MPI_TAG)    = MPI_UNDEFINED

      call mpi_status_set_cancelled( status, .false., ierr)

      call mpi_status_set_elements( status, MPI_BYTE, 0, ierr )

      ierr = MPI_SUCCESS

      end

C

      subroutine free_fn( extrastate, ierr )

      implicit none

      include 'mpif.h'

      integer value, ierr

      include 'attr1aints.h'

      integer freefncall

      common /fnccalls/ freefncall

C

C   For testing purposes, the following print can be used to check whether

C   the free_fn is called

C      print *, 'Free_fn called'

C

      extrastate = extrastate - 1

C   The value returned by the free function is the error code

C   returned by the wait/test function 

      ierr = MPI_SUCCESS

      end

C

      subroutine cancel_fn( extrastate, complete, ierr )

      implicit none

      include 'mpif.h'

      integer ierr

      logical complete

      include 'attr1aints.h'

      ierr = MPI_SUCCESS

      end

C

C

C This is a very simple test of generalized requests.  Normally, the

C MPI_Grequest_complete function would be called from another routine,

C often running in a separate thread.  This simple code allows us to

C check that requests can be created, tested, and waited on in the

C case where the request is complete before the wait is called.  

C

C Note that MPI did *not* define a routine that can be called within

C test or wait to advance the state of a generalized request.  

C Most uses of generalized requests will need to use a separate thread.

C

       program main

       implicit none

       include 'mpif.h'

       integer errs, ierr

       logical flag

       integer status(MPI_STATUS_SIZE)

       integer request

       external query_fn, free_fn, cancel_fn

       include 'attr1aints.h'

       integer freefncall

       common /fnccalls/ freefncall

       errs = 0

       freefncall = 0

       call MTest_Init( ierr )

       extrastate = 0

       call mpi_grequest_start( query_fn, free_fn, cancel_fn, 

     &            extrastate, request, ierr )

       call mpi_test( request, flag, status, ierr )

       if (flag) then

          errs = errs + 1

          print *, 'Generalized request marked as complete'

       endif

       call mpi_grequest_complete( request, ierr )

       call MPI_Wait( request, status, ierr )

       extrastate = 1

       call mpi_grequest_start( query_fn, free_fn, cancel_fn, 

     &                          extrastate, request, ierr )

       call mpi_grequest_complete( request, ierr )

       call mpi_wait( request, MPI_STATUS_IGNORE, ierr )

C       

C      The following routine may prevent an optimizing compiler from 

C      just remembering that extrastate was set in grequest_start

       call dummyupdate(extrastate)

       if (extrastate .ne. 0) then

          errs = errs + 1

          if (freefncall .eq. 0) then

              print *, 'Free routine not called'

          else 

              print *, 'Free routine did not update extra_data'

              print *, 'extrastate = ', extrastate

          endif

       endif

C

       call MTest_Finalize( errs )

       call mpi_finalize( ierr )

       end

C