1:     module ex43fmodule
  2: #include <petsc/finclude/petscvec.h>
  3:       use,intrinsic :: iso_c_binding
  4:       interface
  5:         subroutine fillupvector(vaddr,err) bind ( C, name = 'fillupvector')
  6: !
  7: !     We need to use iso_c_binding variables or otherwise we get compiler warnings
  8: !     Warning: Variable 'vaddr' at (1) is a dummy argument of the BIND(C)
  9: !              procedure 'fillupvector' but may not be C interoperable
 10: !
 11:           use,intrinsic :: iso_c_binding
 12:           integer(c_long_long) vaddr
 13:           integer(c_int) err
 14:         end subroutine fillupvector
 15:       end interface
 16:     end module

 18: #include <petsc/finclude/petscvec.h>
 19:         use,intrinsic :: iso_c_binding
 20:         use petscvec
 21:         use ex43fmodule
 22:        implicit none
 23: !
 24: !  This routine demonstrates how to call a bind C function from Fortran
 25:        Vec            v
 26:        PetscErrorCode ierr
 27:        PetscInt five
 28: !
 29: !     We need to use the same iso_c_binding variable types here or some compilers
 30: !     will see a type mismatch in the call to fillupvector and thus not link
 31: !
 32:        integer(c_long_long) vaddr
 33:        integer(c_int) err

 35:        PetscCallA(PetscInitialize(ierr))
 36:        PetscCallA(VecCreate(PETSC_COMM_WORLD,v,ierr))
 37:        five = 5
 38:        PetscCallA(VecSetSizes(v,PETSC_DECIDE,five,ierr))
 39:        PetscCallA(VecSetFromOptions(v,ierr))
 40: !
 41: !     Now Call a Petsc Routine from Fortran
 42: !
 43: !
 44:        vaddr = v%v
 45:        call fillupvector(vaddr,err)

 47:        PetscCallA(VecView(v,PETSC_VIEWER_STDOUT_WORLD,ierr))
 48:        PetscCallA(VecDestroy(v,ierr))
 49:        PetscCallA(PetscFinalize(ierr))
 50:        end

 52: !/*TEST
 53: !
 54: !   build:
 55: !     depends: ex43.c
 56: !
 57: !   test:
 58: !
 59: !TEST*/