test: add a test case with call to MPI_Wtime

src/mpi_c_bindings.f90

@@ -110,7 +110,7 @@ subroutine c_mpi_allreduce_array(sendbuf, recvbuf, count, datatype, op, comm, ie
             integer(c_int), intent(out), optional :: ierror
         end subroutine c_mpi_allreduce_array
 
-        function c_mpi_wtime() result(time) bind(C, name="mpi_wtime_wrapper")
+        function c_mpi_wtime() result(time) bind(C, name="MPI_Wtime")
             use iso_c_binding, only: c_double
             real(c_double) :: time
         end function

src/mpi_wrapper.c

@@ -203,10 +203,6 @@ void mpi_allreduce_wrapper(const double *sendbuf, double *recvbuf, int *count,
    }
 }
 
-double mpi_wtime_wrapper() {
-    return MPI_Wtime();
-}
-
 void mpi_barrier_wrapper(int *comm_f, int *ierror) {
     MPI_Comm comm = MPI_Comm_f2c(*comm_f);
     *ierror = MPI_Barrier(comm);

tests/wtime_1.f90

@@ -0,0 +1,31 @@
+program wtime_1
+    use, intrinsic:: iso_fortran_env, only: dp=>real64
+    use mpi
+    implicit none
+    integer :: id, Nproc, ierr
+    real(dp) :: wtime
+
+    !>  Initialize MPI.
+    call MPI_Init(ierr)
+
+    !>  Get the number of processes.
+    call MPI_Comm_size(MPI_COMM_WORLD, Nproc, ierr)
+
+    !>  Get the individual process ID.
+    call MPI_Comm_rank(MPI_COMM_WORLD, id, ierr)
+
+    !>  Print a message.
+    if (id == 0) then
+        wtime = MPI_Wtime()
+        print *, 'number of processes: ', Nproc
+    end if
+
+    if (id == 0) then
+        wtime = MPI_Wtime() - wtime
+        print *, 'Elapsed wall clock time = ', wtime, ' seconds.'
+    end if
+
+    !>  Shut down MPI.
+    call MPI_Finalize(ierr)
+
+end program