Fortran 11 and probable 2003 compatibility issue

[laurent_l_]

Hi

I'm using Intel Fortran 11 to create a Fortran-Call-C piece of code

I have problem when passing arguments by value from Fortran to C, and I was wondering if this may come from 2003 support issues in ifort 11

The fortran sends a single argument by value

ival=1 in CALL  p_f_i_AMETest(ival)  

but the C function get the adress instead of the value, and print

ival =1703488 in void AMETest(int ival) 

many thanks for any tips !!

Laurent

This is my code

TestDLL.cpp

extern "C" TESTDLL_API void AMETest(int ival) {

    printf("ival =%d\n",ival);

};

Main.f90

PROGRAM main
        !DEC$ REAL:8
        USE DLLinterface

        CHARACTER*200:: dllname = 'TestDLL.dll'

        Call Test(dllname)
   
END PROGRAM

DLLinterface.f90

MODULE DLLinterface
      
      USE kernel32

      USE, INTRINSIC:: iso_c_binding


      ABSTRACT INTERFACE
        SUBROUTINE f_i_AMETest(ival) BIND(C,name='AMETest')
            use iso_c_binding, only: c_int
            integer(c_int), VALUE :: ival     
        END SUBROUTINE f_i_AMETest
      END INTERFACE
      

      INTEGER(HANDLE):: handleDLL
      PROCEDURE(f_i_AMETest), POINTER:: p_f_i_AMETest     
      TYPE(C_FUNPTR):: p_c_function
      INTEGER(C_INTPTR_T):: addressCpointer
      INTEGER(C_INT):: returnedValue
    
      CONTAINS
        SUBROUTINE Test(DLLname)

            CHARACTER*200, INTENT(IN):: DLLname
            TYPE(C_FUNPTR):: p_c_function
            INTEGER(C_INTPTR_T):: addressCpointer
            INTEGER(C_INT):: returnedValue
            INTEGER(C_INT):: ival
            
            ival=1 
      
            
            handleDLL = LoadLibrary(DLLname)
            
            IF (handleDLL == NULL) THEN
                WRITE(*,*) 'DLLinterface: could not import the DLL'
            ELSE
                WRITE(*,*) 'DLLinterface: DLL imported'
            END IF
            addressCpointer = GetProcAddress(handleDLL, &
                                            'AMETest')
            
            !cast address to a c fonction pointer, then fortran
            CALL C_F_PROCPOINTER( &
                           TRANSFER(addressCpointer,p_c_function), &
                           p_f_i_AMETest)
  
            CALL  p_f_i_AMETest(ival)  

     
       END SUBROUTINE Test
END MODULE DLLinterface

[Steve_Lionel]

You are using a compiler that is some seven (or more!) years old. I have a vague recollection of an old issue with VALUE not being recognized from an ABSTRACT INTERFACE. Please try it with a current compiler (version 17 is current.)

[laurent_l_]

Thanks Doctor Fortran !

Yes I know that my version is old, but I have no other release available right now (and not sure we will buy a new one or update just for the topic I am currently working for)

Any workaround possible in this case ? I really need to load a DLL because this piece of code have to be integrated in an another process.

Thanks

[Lorri_M_Intel · Accepted solution]

I don't have an 11.x compiler available to try this myself, but let me suggest this:

Try adding an explicit %VAL() in your call, as:   CALL  p_f_i_AMETest(%val(ival))

if that gives a compile-time error, let's try using the non-standard directive in the abstract routine declaration:

!DEC$ ATTRIBUTES VALUE :: ival

                  --Lorri

[laurent_l_]

Great ! it has worked !

I need to run more tests with other functions and more arguments, but I'm on the good way now :)

Many thanks Lorri :)