Compiler Warning (level 1) C4561
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Compiler Warning (level 1) C4561

Error Message

'__fastcall' incompatible with the '/clr' option: converting to '__stdcall'

The __fastcall function-calling convention cannot be used with the /clr compiler option. The compiler ignores the calls to __fastcall. To fix this warning, either remove the calls to __fastcall or compile without /clr.

The following sample generates C4561:

// C4561.cpp
// compile with: /clr /W1 /c
// processor: x86
void __fastcall Func(void *p);   // C4561, remove __fastcall to resolve
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