Overview
 About the extra binary file functions
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 The Expand Library features some extra binary low level file acces
 functions. Those are all functions preceded by a 'XPf' (for file), and
 can be seen as an extension to the fopen()/fread() etc.. functions from
 Clipper. Note that you should take care when using these functions, they
 require knowledge of the Operating System.

 the XPferror() function is EXPand's ferror() equivalent for these functions.
 One could always call XPferror() after calling one of the functions in the
 list, it will return 0 for no error, or the appropriate DOS error code.
 Error codes are thus always returned via XPferror(), and not via return
 values of the functions.

 Note that you will find functions to create temporary files without much
 trouble, even on a network environment. This is probably the only way to
 create files where you have the certainty that they are truly unique
 (the functions fcreateNew() and funique()), because fopen()/fcreate()
 always means the possibility that someone else does the same thing
 at the same time. Note also the possibility to lock and unlock binary
 files too, although great care has to be taken when doing this.

 I'd like to stress that you should be aware of the things you are doing
 when you are using these functions. They allow you to acces the files
 directly, no checking is perfmormed (much like in Clipper's f functions).