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Inside Macintosh: Mac OS Runtime Architectures /

Chapter 3 - Programming for the CFM-Based Runtime Architecture / Import Library Techniques

Change Names for Newer Import Libraries

If the new version of the import library cannot support older clients, it is essentially a new library, so the developer could give the new library a different name to eliminate the need for version or symbol checking. For example, you could call a revision to mooLib that is not compatible with older clients mooLib_2.0. However, since the Code Fragment Manager considers libraries with different names to be totally separate libraries, it is possible to have several instantiations of a library present in memory at the same time.

WARNING

By simply renaming an import library, it is possible for one program to end up trying to use two different versions of an import library. For example, say an application uses mooLib and uses a third-party library that also requires mooLib. If the third-party developer decides to upgrade to mooLib_2.0, the application may end up trying to use both mooLib and mooLib_2.0. Because of this danger, the developer should avoid simply renaming newer versions of import libraries. For a safer method, see "Put New Symbols in New Logical Libraries" (page 3-21).