GUID Management

The problem with managing GUIDs is that they are pervasive, and their length prohibits simple comparisons.

The single most important technique in managing GUIDs is to keep a central list of all the GUIDs that are implemented. For example, use the DEFINE_GUID macro or the Guidgen.exe tool with the -n option to generate the required number of GUIDs, and then enter the resulting strings in the first column of a spreadsheet. Each time a new GUID is used, enter a description of its purpose in the second column of the spreadsheet.

Note The DEFINE_GUIDE macro does not generate GUIDs. It defines a 128-bit number to a GUID with a human-readable name.

A central spreadsheet of GUIDs has several advantages:

• Listing all the GUIDs in one location may prevent accidental reuse of a GUID. (This often happens when an application is cloned to create another one.)
• The spreadsheet can be used to compare GUIDs. To check the accuracy of a GUID, you can copy it from the location where it is being used (for example, a .reg file), paste it into the spreadsheet, and then compare the two cells with the = operator.
• A record of GUID usage can be helpful in case of future problems, and this single source of information will be available to find the GUID for an object.