Remove C-Wrapper for MPI_Init

src/mpi.f90

@@ -113,18 +113,21 @@ module mpi
 
     subroutine MPI_Init_proc(ierr)
         use mpi_c_bindings, only: c_mpi_init
-        use iso_c_binding, only : c_int
+        use iso_c_binding, only : c_int, c_ptr, c_null_ptr
         integer, optional, intent(out) :: ierr
-        integer :: local_ierr
+        integer(c_int) :: local_ierr
+        integer(c_int) :: argc
+        type(c_ptr) :: argv = c_null_ptr
+        argc = 0
+        ! Call C MPI_Init directly with argc=0, argv=NULL
+        local_ierr = c_mpi_init(argc, argv)
+
         if (present(ierr)) then
-            call c_mpi_init(ierr)
-        else
-            call c_mpi_init(local_ierr)
-            if (local_ierr /= 0) then
-                print *, "MPI_Init failed with error code: ", local_ierr
-            end if
+            ierr = int(local_ierr)
+        else if (local_ierr /= 0) then
+            print *, "MPI_Init failed with error code: ", local_ierr
         end if
-    end subroutine
+    end subroutine MPI_Init_proc
 
     subroutine MPI_Init_thread_proc(required, provided, ierr)
         use mpi_c_bindings, only : c_mpi_init_thread

src/mpi_c_bindings.f90

@@ -2,10 +2,15 @@ module mpi_c_bindings
     implicit none
 
     interface
-        subroutine c_mpi_init(ierr) bind(C, name="mpi_init_wrapper")
-            use iso_c_binding, only: c_int
-            integer(c_int), intent(out) :: ierr
-        end subroutine c_mpi_init
+        function c_mpi_init(argc, argv) bind(C, name="MPI_Init")
+            use iso_c_binding, only : c_int, c_ptr
+            !> TODO: is the intent need to be explicitly specified
+            !> as 'intent(inout)'? Though, currently LFortran
+            !> errors with this
+            integer(c_int) :: argc
+            type(c_ptr) :: argv
+            integer(c_int) :: c_mpi_init
+        end function c_mpi_init
 
         subroutine c_mpi_init_thread(required, provided, ierr) bind(C, name="mpi_init_thread_wrapper")
             use iso_c_binding, only: c_int

src/mpi_wrapper.c

@@ -4,11 +4,11 @@
 
 #define MPI_STATUS_SIZE 5
 
-void mpi_init_wrapper(int *ierr) {
-    int argc = 0;
-    char **argv = NULL;
-    *ierr = MPI_Init(&argc, &argv);
-}
+// void mpi_init_wrapper(int *ierr) {
+//     int argc = 0;
+//     char **argv = NULL;
+//     *ierr = MPI_Init(&argc, &argv);
+// }
 
 void mpi_init_thread_wrapper(int *required, int *provided, int *ierr) {
     int argc = 0;

tests/init_1.f90

@@ -0,0 +1,36 @@
+program test_mpi_init_rank_size
+    use mpi
+    implicit none
+    integer :: ierr, rank, size
+
+    ! Initialize MPI
+    call MPI_Init(ierr)
+    if (ierr /= MPI_SUCCESS) then
+        print *, "MPI_Init failed with error code: ", ierr
+        stop 1
+    end if
+
+    ! Get rank and size
+    call MPI_Comm_rank(MPI_COMM_WORLD, rank, ierr)
+    if (ierr /= MPI_SUCCESS) then
+        print *, "MPI_Comm_rank failed with error code: ", ierr
+        call MPI_Finalize(ierr)
+        stop 1
+    end if
+
+    call MPI_Comm_size(MPI_COMM_WORLD, size, ierr)
+    if (ierr /= MPI_SUCCESS) then
+        print *, "MPI_Comm_size failed with error code: ", ierr
+        call MPI_Finalize(ierr)
+        stop 1
+    end if
+
+    print *, "Hello from rank ", rank, " of ", size
+
+    ! Finalize MPI
+    call MPI_Finalize(ierr)
+    if (ierr /= MPI_SUCCESS) then
+        print *, "MPI_Finalize failed with error code: ", ierr
+        stop 1
+    end if
+end program test_mpi_init_rank_size