3D Graphics Programming with QuickDraw 3D 1.5.4

About the Error Manager

QuickDraw 3D defines several levels of exceptional conditions that can occur during the execution of QuickDraw 3D routines. An exceptional condition can be an error, a warning, or a notice, depending on the severity of the exceptional condition.

An error is a nonrecoverable condition that causes the currently executing QuickDraw 3D routine to fail. A fatal error is an error whose effects persist even after the call that caused it has ended. Once a fatal error has occurred, all future calls to QuickDraw 3D routines are likely to fail. After a nonfatal error, future calls should be limited to the error determination routines described in this chapter. Although some QuickDraw 3D routine calls made after a nonfatal error might succeed, system operation will be unpredictable and may lead to a system crash or loss of data.
A warning is a condition that, although less severe than an error, might cause an error if your application continues execution without handling the warning.
A notice is a condition that is less severe than a warning and will likely not cause problems. In general, notices indicate inefficiencies or other small problems in using QuickDraw 3D.

QuickDraw 3D notifies your application of errors, warnings, and notices by executing application-defined callback routines you have previously registered with the Error Manager. Once a callback routine is registered, QuickDraw 3D calls it whenever the appropriate condition occurs.

Notices are generated only by debugging versions of the QuickDraw 3D shared library.

You register a callback routine by passing its address to the Q3Error_Register , Q3Warning_Register , or Q3Notice_Register function, depending on whether the callback routine is to handle errors, warnings, or notices. If you do not register a callback routine for errors, the Error Manager calls an internal error handler that attempts to handle the exception. The manner in which the exception handler handles that error can vary, depending on the operating system. For example, on the Macintosh Operating System, the internal exception handler of the debugging version calls the DebugStr function.