It would be nice if permissions were checked eariler when creating parchive.

[Error1000]

Currently when creating a parchive it first per-processes the entire input (par2creator.cpp#L159) then it tries to create the vol files (which happens at this call site par2creator.cpp#L175, or more specifically at this line in the function that is called par2creator.cpp#L692), but if the user doesn't have enough permissions to create the vol file, it crashes, after spending several minutes processing the data.
It would be nice if it checked if it can create the files before attempting to process data to minimize the amount of wasted time.