分段错误 C 和 fortran

Question

------ main.c---------

#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
#include <string.h>

int main()
{   
    char* lib_name = "./a.out";
    int array[5] = {1,2,3,4,5};
    int size_a = sizeof(array)/sizeof(int);            
    void* handle = dlopen(lib_name, RTLD_NOW);
    if (handle) {
        printf("[%s] dlopen(\"%s\", RTLD_NOW): incarcare finalizata\n", 
           __FILE__, lib_name);
    }
    else {
        printf("[%s] nu poate fi deschis: %s\n", __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    void (*subrutine_fortran)(int*, int*) = dlsym(handle, "putere");
    if (subrutine_fortran) {
        printf("[%s] dlsym(handle, \"_set_name\"): simbol gasit\n", __FILE__);
    }
    else {
        printf("[%s] simbol negasit: %s\n", __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }



    subrutine_fortran(&array,&size_a);
    //dlclose(handle);
    for(int i=1;i<4;i++) {
    array[i]=array[i]+1;
    }
}

------ hello.f90 --------

subroutine putere(a,h) bind(c)
    use ISO_C_BINDING
    implicit none
    integer(c_int) :: h
    integer(c_int), dimension(h) :: a
    integer i
    do concurrent (i=0:5)
        a(i)=a(i)*10
    end do
    !write (*,*) a
end subroutine

When I do a loop through array elements:

for(int i=1;i<4;i++) {
  array[i]=array[i]+1;
}

I get a segmentation fault.

It doesn't happen when I write:

array[3]=array[3]+1

Answer 1

Your C-code is this:

int array[5] = {1,2,3,4,5};
int size_a = sizeof(array)/sizeof(int);            

subrutine_fortran(&array,&size_a);

and your Fortran code is this:

subroutine putere(a,h) bind(c)
    use ISO_C_BINDING
    implicit none
    integer(c_int) :: h
    integer(c_int), dimension(h) :: a
    integer i
    do concurrent (i=0:5)
        a(i)=a(i)*10
    end do
    !write (*,*) a
end subroutine

This is wrong a couple of ways - as Zack points out, Fortran arrays are 1-indexed (even when they come from somewhere else, like C). So this should start at 1. Also, if 0 was right, the size would be wrong. You want something like

    do concurrent (i=1:h)

With that change, it works for me.