Core Foundation Libraries

When Core Foundation is installed on a Mac OS 9 systems, you have two libraries at your disposal: a production library (CoreFoundationLib) and a debug library (CoreFoundationLib Debug). When you use the debug version of the library you automatically get assertion checking on common programming errors such as

• accessing a collection out of bounds

• attempting to change an immutable object

• passing an argument of a wrong type

Currently assertions print a log message and cause a break in the debugger.

The production version of the Core Foundation library is optimized and performs no error checking; invalid parameters, even references to the wrong Core Foundation type, will cause indeterminate and probably incorrect behavior. Obviously, you should use the debug version of the Core Foundation library during development to catch errors in programming.

On Mac OS X, Core Foundation is a framework: a package consisting of a dynamic shared library and associated resources, including public header files. CoreFoundation.framework also includes a production version and a debug version of the library. To use the debug version, set the environment variable DYLD_IMAGE_SUFFIX to _debug before running the application; the dynamic linker will then check for and link against the debug versions of any dynamic libraries, such as Core Foundation, that your application uses.