file_length IS length of file in bytes, but thats cool, because YOU are not going to use it for anything.

'file_length' is only used to compare with 'file_seek', which is also in bytes.
ALL it is doing is checking to see if youve hit the physical end of the file.
Once that happens, it stops reading by exiting the loop, and you then use the
value accumulated in "var_counter" to see how many actual numbers were retrieved...

Forget the second version if you dont have any limits on the data ranges.

I dont get where there is a problem handling multiple files either.
Are they all READ-ONLY text files?
Or are they somewhat dynamic, being created on-the-fly by another part of the program?