CODEWITHSUNDEEP
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C-va
C-va

Reputation: 2920

How to use multiple idl files in ATL (COM) Project for .Net C# VS 2012

I'm new to C++/COM. I have created a ATL COM Project with a callback mechanism to send messages to managed side. It has one idl file (sample1.idl) which expose 'n' number of methods, hence managed environment can access it. Now i would like to add another .idl(sample2.idl) file to that project. .tlb is created for both sample1 & sample2 and build succeeded. On browsing the .dll , I couldn't find the sample2.idl related stuffs. I suspect that .tlb generated from ‘sample2.idl’ is not reflected in the .dll.

Can we have more than one IDL’s in the ATL (COM) project ?

Upvotes: 1

Views: 975

Answers (1)

Hans Passant
Hans Passant

Reputation: 942328

The default for ATL, as with many native build environments, is to embed the type library as a resource in the DLL. Something you can see in Visual Studio (retail edition required), use File + Open + File and select the DLL. Open the "TYPELIB" node, you'll see one type library with resource ID #1. This is the one that Visual Studio sees when you use Add Reference.

Most any build tool that consumes type libraries will only ever look for that one resource. Visual Studio is no exception. It also can encode only one type library in its project files. You perhaps can make it work by selecting the 2nd .tlb file with the Add Reference dialog. Albeit that it is very likely that you'll now get exposed to more problems in your ATL project, like forgetting to register that 2nd type library in your .rgs file.

Very hard to give proper advice without any hint what that second IDL file might contain. Stay out of trouble by merging them or by using the existing support in IDL to import other .idl files or type libraries.

Upvotes: 1

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