Type Casts

The different types of casts which are supported in the interface of the objects.

Casts are mostly used to change a pointer pointing to type a into a pointer pointing to type b. a and b must be structural compatible. They both must have the same members (type + name).

Summary

Type Casts	The different types of casts which are supported in the interface of the objects.
casting pointers
genericcast_TYPE	If an interface subtype is constructed with help of TYPE_it_DECLARE it is compatible with TYPE_it.
FROMTYPEcast_TYPE	The same as genericcast except that function FROMTYPEcast_TYPE(...)
cast_TYPE	If you do not need a generic cast and have only one FROMTYPEcast_TYPE you can rename it into cast_TYPE.
asTOTYPE	This cast reverses the type conversion.

casting pointers

Summary

genericcast_TYPE	If an interface subtype is constructed with help of TYPE_it_DECLARE it is compatible with TYPE_it.
FROMTYPEcast_TYPE	The same as genericcast except that function FROMTYPEcast_TYPE(...)
cast_TYPE	If you do not need a generic cast and have only one FROMTYPEcast_TYPE you can rename it into cast_TYPE.
asTOTYPE	This cast reverses the type conversion.

genericcast_TYPE

If an interface subtype is constructed with help of TYPE_it_DECLARE it is compatible with TYPE_it. To cast a pointer to subtype into a pointer to TYPE_it use genericcast_TYPEit(...). This function which is implemented as macro checks the compatibility.

FROMTYPEcast_TYPE

The same as genericcast except that function FROMTYPEcast_TYPE(...) casts a pointer to FROMTYPE into a pointer to TYPE. This cast is more specific and does only accepts pointers to FROMTYPE.

cast_TYPE

If you do not need a generic cast and have only one FROMTYPEcast_TYPE you can rename it into cast_TYPE.

asTOTYPE

This cast reverses the type conversion. The function asTOTYPE_TYPE converts a pointer to TYPE into a pointer to TOTYPE. It is considered an extension of TOTYPE. The same functionality could be achieved with function TYPEcast_TOTYPE implemented as part of the interface of TOTYPE. Therefore it is encouraged to implement always TYPEcast_TOTYPE even in another module. Type extensions will be supported by the upcoming language “transactional C”.