You can extract files from a cabinet in two ways. The first and simplest way is to take advantage of the automatic cabinet processing built into the setup functions.
The installation functions, such as SetupCommitFileQueue, SetupInstallFile, and SetupInstallFromInfSection, check the compression on each file. If the file is in a cabinet, the functions first search for a file of that name outside the cabinet. If found, the functions install the external file, ignoring the file inside the cabinet. This enables you to update a single file inside the cabinet without rebuilding the cabinet.
The setup functions also track which files in a cabinet have been retrieved, so that a file is extracted only once, even if it is installed several times.
The second way to extract files from a cabinet is by using SetupIterateCabinet. This function iterates through each file in a cabinet, sending a notification to a callback routine for each file found. The callback routine then returns a value that indicates whether the file should be extracted or skipped.
Note The Setup API does not supply a default callback routine to handle cabinet notifications. If you call SetupIterateCabinet explicitly, you must supply a callback routine to process the cabinet notifications that the function returns.