error #791: calling convention specified more than once

[phastphill]

I recently upgraded the Intel C++ Compiler in my build environment from v11 (067) to v12 (12.0.1.127 Build 20101116).

With the new compiler, I get error #791 when compiling rpcndr.h (a header in the MS Windows DDK). The same file compiles without issue with v11.

The offending lines of code are lines 1428-1446:

RPCRTAPI

unsigned char * RPC_ENTRY

RPC_ENTRY

NdrCsArrayUnmarshall(

PMIDL_STUB_MESSAGE pStubMsg,

unsigned char ** ppMemory,

PFORMAT_STRING pFormat,

unsigned char fMustAlloc

);

RPCRTAPI

unsigned char * RPC_ENTRY

RPC_ENTRY

NdrCsTagUnmarshall(

PMIDL_STUB_MESSAGE pStubMsg,

unsigned char ** ppMemory,

PFORMAT_STRING pFormat,

unsigned char fMustAlloc

);

Documentation of the error is sparse:

http://software.intel.com/en-us/articles/cdiag791/

Why does this cause errors in v12 and not with v11?

Thanks,

Phill Williams

[Judith_W_Intel · Accepted solution]

This diagnostic is never an error by default. It is only a warning. You must be doing something special (like using the /WX command line option) to turn this warning into an error.

The warning occurswhen you specify the same calling convention more than once on a functiondeclaration, i.e.:

void __cdecl __cdecl foo();

If you preprocess the file (using -E or -P) you should be able to see the actual declarations after macro expansion.

Judy

[phastphill]

Thank you -- it appears that the WDK build infrastructure inserts /WX by default. Overriding this fixed my build.