XPfcommit()
   commit all buffered data to disk
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   Function:   XPfcommit()

               this function commits all data related to a specific handle
               to disk. Like fclose() and fopen(), by ensuring that all
               buffers are flushed to disk. Rarely necessary in binary
               files, but supported anyway.

               Requires DOS 3.30 or higher!

   Syntax:     fcommit(h) --> NIL

   Arguments:  <h> is that handle of the file to commit.
               file must be open, of course.

   Returns:    NIL

   Usage: