In C, a function `void func()` doesn't declare a function without arguments, instead it declares a function that takes unspecified number of arguments. The correct way to declare a function that takes no arguments is to use the `void` keyword: `void func(void)`.

What is the correct way to refer to such a function (`void func()`) from D bindings?

If I assume that the unspecified number of arguments (for some particular function) is equal to zero, is `extern (C) void func()` a correct D binding to the both functions `void func()` and `void func(void)` declared in C?

Specifically, I'm concerned about calling convention issues.

On Friday, 29 July 2016 at 10:57:37 UTC, ciechowoj wrote:
> In C, a function `void func()` doesn't declare a function without arguments, instead it declares a function that takes unspecified number of arguments. The correct way to declare a function that takes no arguments is to use the `void` keyword: `void func(void)`.
>
> What is the correct way to refer to such a function (`void func()`) from D bindings?
>
> If I assume that the unspecified number of arguments (for some particular function) is equal to zero, is `extern (C) void func()` a correct D binding to the both functions `void func()` and `void func(void)` declared in C?
>
> Specifically, I'm concerned about calling convention issues.

Yes, this is correct as long as the calling convention is not stdcall or something else:

extern(C) void func();

If you're dealing with stdcall:

extern(Windows) void func();

And if it is a cross-platform library that is stdcall on Windows and cdecl elsewhere:

extern(C) void fun();

On Friday, 29 July 2016 at 12:15:22 UTC, Mike Parker wrote:

>
> Yes, this is correct as long as the calling convention is not stdcall or something else:

Though, I should add the caveat that you need to ensure the definition of the C function does not specify any parameters. AFAIK, this is legal:

// foo.h
void func();

// foo.c
void func(int a, int b) { ... }

In which case you would want to include the parameters in your binding.

On Friday, 29 July 2016 at 12:20:17 UTC, Mike Parker wrote:
>
> Though, I should add the caveat that you need to ensure the definition of the C function does not specify any parameters. AFAIK, this is legal:
>
> // foo.h
> void func();
>
> // foo.c
> void func(int a, int b) { ... }
>
> In which case you would want to include the parameters in your binding.

Thanks, good to know.

On 07/29/2016 02:15 PM, Mike Parker wrote:
> And if it is a cross-platform library that is stdcall on Windows and
> cdecl elsewhere:
>
> extern(C) void fun();

extern(System), no?

On Friday, 29 July 2016 at 18:24:52 UTC, ag0aep6g wrote:
> On 07/29/2016 02:15 PM, Mike Parker wrote:
>> And if it is a cross-platform library that is stdcall on Windows and
>> cdecl elsewhere:
>>
>> extern(C) void fun();
>
> extern(System), no?

Yeah, that's what I had intended.