CALLCONV

Identifies the calling convention used by a member function described in the METHODDATA structure.

typedef /* [v1_enum] */ 
enum tagCALLCONV{
    CC_FASTCALL    = 0,
    CC_CDECL    = 1,
    CC_MSCPASCAL    = CC_CDECL + 1,
    CC_PASCAL    = CC_MSCPASCAL,
    CC_MACPASCAL    = CC_PASCAL + 1,
    CC_STDCALL    = CC_MACPASCAL + 1,
    CC_FPFASTCALL    = CC_STDCALL + 1,
    CC_SYSCALL    = CC_FPFASTCALL + 1,
    CC_MPWCDECL    = CC_SYSCALL + 1,
    CC_MPWPASCAL    = CC_MPWCDECL + 1,
    CC_MAX    = CC_MPWPASCAL + 1
    }    CALLCONV;
 

On 16-bit Windows systems, functions implemented with the CC_CDECL calling convention cannot have a return type of float or double. This includes functions that return DATE, which is a floating-point type.