Windows Can but Won't

摘要

WINDOWS ACTUALLY can replace a DLL that is in use by renaming the original then copying the new file into place. However, the Windows world prefers not to do this. Why? Even if you replace a file that is in use, there may still be code in the system that wants to use the old version. For example, suppose you have two files, A.DLL and B.DLL, which work together. You issue a patch that updates both of the files, but A.DLL is in use. No problem. You simply replace both of them. As a result, programs that were still using A.DLL keep using the old version, but new programs will use the new one. And all programs get the new version of B.DLL.