Technical Q&A's

HW 01 - Determining If a PCI Bus Exists (1-May-95)

Q How do I determine if the PowerMacintosh has PCI expansion slots?

A If there is a Name Registry, you can use it to determine if a PCI bus exists. To do this, use RegistryEntrySearch to locate an entry/node having a known property/value, propertyName = "device_type", and propertyValue = "pci" If an entry is found that has the known property/value (noErr and done = "False"), there is a PCI bus.

To allow you to determine if the NameRegistry exists, the Gestalt Manager selector 'nreg' was added to the version of system software that comes with the machine. If the NameRegistry exists, the value returned is the version number of the Name Registry. If the NameRegistry does not exist, a gestaltUndefSelectorErr is returned. If the Name Registry does not exist, you can assume that the machine is NuBus-based and work accordingly.

Technical Support
Technical Q&As
Contents | Next Question