Hi. I try to interface D module with C one. See:

* file test.c:
#include <stdio.h>
int c_var;
int func()
{
    c_var = 1234;
    printf("In C\n");
    printf("c_var = %d\n", c_var);
    printf("&c_var = %x\n", &c_var);
    return 0;
}

* file unit.d:
module unit;
import std.stdio;
extern(C){
    int c_var;
    int func();
}

void main()
{
    func();
    writeln("In D");
    writefln("c_var = %d", c_var);
    writefln("&c_var = %x", &c_var);
}

And compile:
    dmc -c test.c
    dmd unit.d test.obj

I'd like to call C functions and use C variables in D module. D calls C functions just fine, but how can I use C variables?

This program outputs:
In C
c_var = 1234
&c_var = 45d004
In D
c_var = 0
&c_var = 14298c

On 26/06/2011 20:54, Alex_Dovhal wrote:
> I'd like to call C functions and use C variables in D module.
> D calls C functions just fine, but how can I use C variables?

extern(C) extern int myCVar;

-- 
Robert
http://octarineparrot.com/

"Robert Clipsham" <robert@octarineparrot.com> wrote:
> On 26/06/2011 20:54, Alex_Dovhal wrote:
>> I'd like to call C functions and use C variables in D module. D calls C functions just fine, but how can I use C variables?
>
> extern(C) extern int myCVar;

Thanks for answer. I've already tried that, it doesn't work for some reason:

* file unit2.d:
module unit;
import std.stdio;
extern(C) int func();
extern(C) extern int c_var;

void main()
{
    func();
    writeln("In D");
    writefln("c_var = %d", c_var);
    writefln("&c_var = %x", &c_var);
}

Result:
In C
c_var = 1234
&c_var = 470200
In D
object.Error: Access Violation
----------------
426DA4
426C1B
405BEB
4057E7
451099
----------------


Found workaround, but it's extreme hack:

*file test.c
#include <stdio.h>
int c_var;
//int* ref_c_var()
//{
//    return &c_var;
//}

#define REF_DECL(type, name) type* ref_ ## name () {return &name;}

REF_DECL(int, c_var)

int func()
{
    c_var = 1234;
    printf("In C\n");
    printf("c_var = %d\n", c_var);
    printf("&c_var = %x\n", &c_var);
    return 0;
}

*file: unit1.d:
module unit;
import std.stdio;

extern(C) int func();

string C_VAR(string type, string name)
{
    return
        "extern (C) "~ type ~ "* ref_" ~ name ~ "();"~
        " " ~ "ref " ~ type ~ " " ~ name ~"(){return *ref_"~name~"();}";
}

mixin(C_VAR("int", "c_var"));

void main()
{
    func();
    writeln("In D");
    writefln("c_var = %d", c_var);
    writefln("&c_var = %x", &c_var);
}

On Sun, Jun 26, 2011 at 5:00 PM, Alex_Dovhal <alex_dovhal@yahoo.com> wrote:

> "Robert Clipsham" <robert@octarineparrot.com> wrote:
> > On 26/06/2011 20:54, Alex_Dovhal wrote:
> >> I'd like to call C functions and use C variables in D module. D calls C functions just fine, but how can I use C variables?
> >
> > extern(C) extern int myCVar;
>
> Thanks for answer. I've already tried that, it doesn't work for some reason:
>
> * file unit2.d:
> module unit;
> import std.stdio;
> extern(C) int func();
> extern(C) extern int c_var;
>
> void main()
> {
>    func();
>    writeln("In D");
>    writefln("c_var = %d", c_var);
>    writefln("&c_var = %x", &c_var);
> }
>
> Result:
> In C
> c_var = 1234
> &c_var = 470200
> In D
> object.Error: Access Violation
> ----------------
> 426DA4
> 426C1B
> 405BEB
> 4057E7
> 451099
> ----------------
>
>
> Found workaround, but it's extreme hack:
>
> *file test.c
> #include <stdio.h>
> int c_var;
> //int* ref_c_var()
> //{
> //    return &c_var;
> //}
>
> #define REF_DECL(type, name) type* ref_ ## name () {return &name;}
>
> REF_DECL(int, c_var)
>
> int func()
> {
>    c_var = 1234;
>    printf("In C\n");
>    printf("c_var = %d\n", c_var);
>    printf("&c_var = %x\n", &c_var);
>    return 0;
> }
>
> *file: unit1.d:
> module unit;
> import std.stdio;
>
> extern(C) int func();
>
> string C_VAR(string type, string name)
> {
>    return
>        "extern (C) "~ type ~ "* ref_" ~ name ~ "();"~
>        " " ~ "ref " ~ type ~ " " ~ name ~"(){return *ref_"~name~"();}";
> }
>
> mixin(C_VAR("int", "c_var"));
>
> void main()
> {
>    func();
>    writeln("In D");
>    writefln("c_var = %d", c_var);
>    writefln("&c_var = %x", &c_var);
> }
>
>
>

It works for me like this:

extern(C){
   __gshared int c_var;
   int func();
}

"Jimmy Cao" <jcao219@gmail.com> wrote:
>It works for me like this:
>
>extern(C){
>   __gshared int c_var;
>   int func();
>}

Thanks.