exten(C) {
    testFunction(int function(int));
}

testFunction now requires an external function as parameter. It can't be called with a pointer to a D function.

Logical Solution:

extern(C) {
    testFunction(extern(D) int function(int)); // DOES NOT COMPILE
}

How do you fix this without moving it outside the global extern block?

On Tuesday, 15 April 2014 at 20:15:42 UTC, Jeroen Bollen wrote:
> exten(C) {
>     testFunction(int function(int));
> }
>
> testFunction now requires an external function as parameter. It can't be called with a pointer to a D function.
>
> Logical Solution:
>
> extern(C) {
>     testFunction(extern(D) int function(int)); // DOES NOT COMPILE
> }
>
> How do you fix this without moving it outside the global extern block?

Whoops, assume testFunction is defined as "void testFunction(...)"

C has no knowledge of D ABI so this can't work. If you just want to store D function pointer to later retrieve it and call from D code, you can as well store it as void* (or extern(C) with similar signature to preserve part of type) and cast upon interfacing.

On Tuesday, 15 April 2014 at 20:19:36 UTC, Dicebot wrote:
> C has no knowledge of D ABI so this can't work. If you just want to store D function pointer to later retrieve it and call from D code, you can as well store it as void* (or extern(C) with similar signature to preserve part of type) and cast upon interfacing.

Hmm so the function passed should be declared as extern C but be defined nonetheless? That makes sense.

On 04/15/14 22:15, Jeroen Bollen wrote:
> exten(C) {
>     testFunction(int function(int));
> }
> 
> testFunction now requires an external function as parameter. It can't be called with a pointer to a D function.
> 
> Logical Solution:
> 
> extern(C) {
>     testFunction(extern(D) int function(int)); // DOES NOT COMPILE
> }
> 
> How do you fix this without moving it outside the global extern block?

   extern(C) {
       extern (D) alias FP = int function(int);
       void testFunction(FP);
   }

artur

On Tuesday, 15 April 2014 at 22:32:10 UTC, Artur Skawina wrote:
>    extern(C) {
>        extern (D) alias FP = int function(int);
>        void testFunction(FP);
>    }
>
> artur

Still does not allow you to actually call it from C side, so this is somewhat confusing.

I'd really just go with void*