Intrinsic Data Types

The following data types are recognized by MIDL.

Type	Description
boolean	Data item that can have the value True or False. The size maps to VARIANT_BOOL.
char	8-bit signed data item.
double	64-bit IEEE floating-point number.
int	Signed integer, whose size is system dependent.
float	32-bit IEEE floating point number.
long	32-bit signed integer.
short	16-bit signed integer.
wchar_t	Unicode character accepted only for 32-bit type libraries.
BSTR	Length-prefixed string, as described in Dispatch Interface and API Functions.
CURRENCY	8-byte, fixed-point number.
DATE	64-bit floating-point fractional number of days since December 30, 1899.
DECIMAL	96-bit unsigned binary integer scaled by a variable power of 10. Provides a size and scale for a number.
SCODE	Built-in error type that corresponds to VT_ERROR. Essentially identical to an HRESULT.
VARIANT	One of the variant data types as described in Dispatch Interface and API Functions.
IDispatch *	Pointer to the IDispatch interface.
IUnknown *	Pointer to the IUnknown interface. (Any OLE interface can be represented by its IUnknown interface.)
SAFEARRAY(TypeName)	TypeName is any of the above types. Array of these types.
TypeName*	TypeName is any of the above types. Pointer to a type.
void	Allowed only as return type for a function, or in a function parameter list to indicate no arguments.
HRESULT	Return type used for reporting error information in interfaces, as described in COM Programmer's Reference.
LPWSTR	Unicode string accepted only for 32-bit type libraries.
LPSTR	Zero-terminated string.

 

Not all of the above types can be marshaled by Automation to another process or thread. The list of types that can be marshaled are called Automation compatible types, and are listed under the oleautomation attribute description.

The keyword unsigned can be specified before int, char, short, and long.