base_types

Remarks

All data transmitted on the network during a remote procedure call must resolve to a base type or predefined type.

MIDL supports the following base types: int, boolean, byte, char, double, float, handle_t, hyper, long, short, small, and void *. The keywords signed and unsigned can be used to qualify integer and character types. MIDL also provides the predefined types error_status_t and wchar_t.

Note The boolean base type is not compatible with the oleautomation attribute. Use VARIANT_BOOL in your Automation-compatible interfaces.

Base types can appear as type specifiers in const declarations, typedef declarations, general declarations, and as parameter type specifiers in function declarators.

The base and predefined types have the following default signs and sizes:

Base type	Default sign	Description
boolean	unsigned	8-bit data item
byte	- (not applicable)	8-bit data item
char	unsigned	8-bit unsigned data item
double	-	64-bit floating-point number
float	-	32-bit floating-point number
handle_t	-	Primitive handle type
hyper	signed	64-bit signed integer
int	signed	32-bit signed integer
long	signed	32-bit signed integer
short	signed	16-bit signed integer
small	signed	8-bit signed integer
void *	-	32-bit context handle pointer type
wchar_t	unsigned	16-bit unsigned data item

Any other types in the interface must be derived from these base or predefined types. The following restrictions apply to data types in interfaces:

On 16-bit platforms, the type int cannot appear in remote functions without a size qualifier such as short, small, long or hyper.
The type void * cannot appear in remote functions except when it is used to define a context handle.
DCE IDL compilers do not recognize the keyword signed. Therefore, this feature is not available when you use the MIDL compiler /osf switch.

base_types

Remarks

See Also