URx for DOS/OS2 files

I am porting the library to OS/2 and am trying to make local file access 
work.  Is there a standard way to reference a DOS or OS/2 file?  IBM 
WebExplorer uses:
Is this what I should put in the library (HTParse) for OS/2?  This scheme 
looks as good as any to me and should be pretty easy to do.