Technical Q&A PLAT23

The InterfaceLibSys7.additions Stub Library

Q: I'm trying to use the SystemSevenFiveOrLater gestalt.h functions NewGestaltValue and SetGestaltValue from a PPC application. They are not defined in InterfaceLib. Could you tell me where I can find them?

A: It might seem that Apple should ship an new InterfaceLib stub library with the additional System 7.5 symbols. By default, however, the new symbols would not be weak linked, and they would therefore send developers down the path of creating binaries that don't run on System 7.1.

Instead, Apple has created a separate stub library, InterfaceLibSys7.additions, which contains only the new System 7.5 InterfaceLib symbols. Since it is a separate file, it is easier to weak-link (and to remember to weak-link!).

In Metrowerks, use the pop up next to the file-in-project window and mark the whole library weak-linked. In MPW, use -weak and list the new System 7.5 functions used.

Download Binhexed MetroWerks library file (2K)