I'm getting a strange compilation error with a COM interface I'm trying to access. Here's the relevant part of the interface:

extern(Windows) interface IASIO : IUnknown
{
    ASIOBool init(void*);
[snip]
    ASIOError getChannels(long*, long*);
[snip]
}

And here's the problem:

test.init(null); // Error: function expected before (), not null of type IASIO*
test.getChannels(&ichans, &ochans); // compiles

test is of type IASIO*. ASIOBool and ASIOError are both aliases for long. The null in the "init" is not the problem; if I give the function the correct pointer it doesn't compile as well.

Has anybody any idea why one call compiles and the other doesn't?

-Mike

"Mike" <vertex@gmx.at> wrote in message news:fiuejb$2j6g$1@digitalmars.com...
> I'm getting a strange compilation error with a COM interface I'm trying to access. Here's the relevant part of the interface:
>
> extern(Windows) interface IASIO : IUnknown
> {
>    ASIOBool init(void*);
> [snip]
>    ASIOError getChannels(long*, long*);
> [snip]
> }
>
> And here's the problem:
>
> test.init(null); // Error: function expected before (), not null of type
> IASIO*
> test.getChannels(&ichans, &ochans); // compiles
>
> test is of type IASIO*. ASIOBool and ASIOError are both aliases for long. The null in the "init" is not the problem; if I give the function the correct pointer it doesn't compile as well.
>
> Has anybody any idea why one call compiles and the other doesn't?

That's certainly odd, but you don't/shouldn't be using an IASIO*. Interfaces are already reference types, so where you'd use an IASIO* in C/C++, use an IASIO in D.

"Jarrett Billingsley" <kb3ctd2@yahoo.com> wrote in message news:fiuib6$2oiq$1@digitalmars.com...
> "Mike" <vertex@gmx.at> wrote in message news:fiuejb$2j6g$1@digitalmars.com...
>> I'm getting a strange compilation error with a COM interface I'm trying to access. Here's the relevant part of the interface:
>>
>> extern(Windows) interface IASIO : IUnknown
>> {
>>    ASIOBool init(void*);
>> [snip]
>>    ASIOError getChannels(long*, long*);
>> [snip]
>> }
>>
>> And here's the problem:
>>
>> test.init(null); // Error: function expected before (), not null of type
>> IASIO*
>> test.getChannels(&ichans, &ochans); // compiles
>>
>> test is of type IASIO*. ASIOBool and ASIOError are both aliases for long. The null in the "init" is not the problem; if I give the function the correct pointer it doesn't compile as well.
>>
>> Has anybody any idea why one call compiles and the other doesn't?
>
> That's certainly odd, but you don't/shouldn't be using an IASIO*. Interfaces are already reference types, so where you'd use an IASIO* in C/C++, use an IASIO in D.

And it just dawned on me why the init isn't working: init is a property of all D types and variables.  The second one works because the . there is working like -> in C.

init should then work fine if you use an IASIO.

Ah! Of course! I translated the SDK from C++, where it's all pointers, and didn't care (excactly because "." does (usually) behaves like "->"). Now it's all IASIO without pointers.

Thanks!

-Mike

Jarrett Billingsley Wrote:

> "Jarrett Billingsley" <kb3ctd2@yahoo.com> wrote in message news:fiuib6$2oiq$1@digitalmars.com...
> > "Mike" <vertex@gmx.at> wrote in message news:fiuejb$2j6g$1@digitalmars.com...
> >> I'm getting a strange compilation error with a COM interface I'm trying to access. Here's the relevant part of the interface:
> >>
> >> extern(Windows) interface IASIO : IUnknown
> >> {
> >>    ASIOBool init(void*);
> >> [snip]
> >>    ASIOError getChannels(long*, long*);
> >> [snip]
> >> }
> >>
> >> And here's the problem:
> >>
> >> test.init(null); // Error: function expected before (), not null of type
> >> IASIO*
> >> test.getChannels(&ichans, &ochans); // compiles
> >>
> >> test is of type IASIO*. ASIOBool and ASIOError are both aliases for long. The null in the "init" is not the problem; if I give the function the correct pointer it doesn't compile as well.
> >>
> >> Has anybody any idea why one call compiles and the other doesn't?
> >
> > That's certainly odd, but you don't/shouldn't be using an IASIO*. Interfaces are already reference types, so where you'd use an IASIO* in C/C++, use an IASIO in D.
> 
> And it just dawned on me why the init isn't working: init is a property of all D types and variables.  The second one works because the . there is working like -> in C.
> 
> init should then work fine if you use an IASIO.
> 
> 

May I suggest to have a look at :
http://www.dsource.org/projects/juno/wiki/TypeLibraryImporter

you'll find worthfull COM information and a nice tool to automate this task.
HTH Bjoern

Mike schrieb:
> I'm getting a strange compilation error with a COM interface I'm trying to access. Here's the relevant part of the interface:
> 
> extern(Windows) interface IASIO : IUnknown
> {
>     ASIOBool init(void*);
> [snip]
>     ASIOError getChannels(long*, long*);
> [snip]
> }
> 
> And here's the problem:
> 
> test.init(null); // Error: function expected before (), not null of type IASIO*
> test.getChannels(&ichans, &ochans); // compiles
> 
> test is of type IASIO*. ASIOBool and ASIOError are both aliases for long. The null in the "init" is not the problem; if I give the function the correct pointer it doesn't compile as well.
> 
> Has anybody any idea why one call compiles and the other doesn't?
> 
> -Mike