Description of the no_function_mapping compiler directive and the implementation_key compiler directive in Visual C++ .NET or in Visual C++ 2005 (832688)
The information in this article applies to:
- Microsoft Visual C++ .NET (2002)
- Microsoft Visual C++ 2005 Express Edition
SUMMARYThis article describes the no_function_mapping compiler
directive and the implementation_key compiler directive. This article also describes the compiler errors that you may receive when you use the implementation_key compiler directive. Additionally, it describes how you can resolve the compiler errors for the implementation_key compiler directive.SYMPTOMS When you compile the code, you may receive the following
error message: error 2143: syntax error : missing
';' CAUSEThe implementation_key compiler directive is a
compiler-injected directive that is used when a Component Object Model (COM)
interface has more than 1000 methods. The Microsoft Visual C++ compiler inserts
the implementation_key compiler directive in the TypeLib Information (TLI) Object Library and in the Type Library Header (TLH) files. The injected code may look
similar to the following code:
#pragma start_map_region ("...\Namesp.tli")
__declspec(implementation_key(1)) <a method prototype>
__declspec(implementation_key(2)) <a method prototype>
When large numbers of methods are used in the Interface Description
Language (IDL) file, the Visual C++ compiler starts to use the #pragma implementation_key compiler directive
for each function to improve performance. The #pragma implementation_key compiler directive may
cause some side effects, and you may receive the compiler errors in the TLI
file that are mentioned in Symptoms section. RESOLUTIONYou can disable the implementation_key compiler directive by adding the undocumented no_function_mapping compiler directive to
your #import statement as follows: #import "Dllname.dll" no_function_mapping This code removes the #pragma implementation_key compiler directive from the TLI file and resolves the compiler
errors. STATUS This behavior is by design.
| Modification Type: | Major | Last Reviewed: | 1/12/2006 |
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| Keywords: | kbtshoot kbprb kbCompiler kbDLL kberrmsg kbinfo KB832688 kbAudDeveloper |
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