This function allows you to notify user about the progress when you un/pack files.

 

void __stdcall SetProcessDataProc (HANDLE hArcData, tProcessDataProc pProcessDataProc);

 

 

pProcessDataProc contains a pointer to a function that you may want to call when notifying user about the progress being made when you pack or extract files from an archive. You need to store the value at some place if you want to use it; you can use hArcData that you have returned by OpenArchive to identify that place.