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December 02, 2007
COM/interface question
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
December 02, 2007
Re: COM/interface question
"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.
December 02, 2007
Re: COM/interface question
"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.
December 02, 2007
Re: COM/interface question
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. 
> 
>
December 03, 2007
Re: COM/interface question
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
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