成员指针地址更改

Question

在下面的代码中，我检查int* j的内部和之后的Mystruct的{​​{1}}的地址。地址在每种情况下都不同。有什么问题吗？

C ++

Mystruct

Fortran驱动程序

struct Mystruct
{
    int* j;

    Mystruct()
    {
        j = new int;
        *j = 8;

        check_address();
    }

    void check_address()
    {
        std::cout << j << std::endl;
    }
};        

typedef void* OpaqueObject;

extern "C"
{    
    OpaqueObject allocate_mystruct()
    {
        Mystruct* ms = new Mystruct();
        return reinterpret_cast<OpaqueObject>(ms);
    }    

    void check_address(OpaqueObject** oo)
    {
        Mystruct *ms = (Mystruct*)(**oo);
        ms->check_address();
    }
}

Fortran模块

program main

    use mpi
    use mymodule, only : f_allocate_mystruct, f_check_address
    IMPLICIT NONE

    integer error

    call MPI_Init(error)    

    call f_allocate_mystruct()
    call f_check_address()

    call MPI_Finalize (error)

    end

编辑

根据一些程序员dude的评论修改module mymodule use mpi use, intrinsic :: ISO_C_Binding, only: c_ptr, c_null_ptr implicit none private interface function allocate_mystruct() result(optr) bind(C, name="allocate_mystruct") import c_ptr implicit none type(c_ptr) :: optr end function allocate_mystruct subroutine check_address(optr) bind(C, name="check_address") import :: c_ptr implicit none type(c_ptr), intent(in) :: optr end subroutine check_address end interface type(c_ptr), save :: c_mystruct = c_null_ptr public :: f_allocate_mystruct, f_check_address CONTAINS subroutine f_check_address() if(c_associated(c_mystruct)) then call check_address(c_mystruct); end if end subroutine f_check_address subroutine f_allocate_mystruct() c_mystruct = allocate_mystruct() end subroutine f_allocate_mystruct end module mymodule 接口解决了该问题。

check_address