pcxPlanes()

         Returns the number of planes of the PCX

    Syntax:

         pcxPlanes ( cFile ) -> nPlanes

         cFile : Name of the PCX file

    Description:

         This function returns the number of planes of the PCX file if it
         exists and it has a PCX format. Else returns Nil

    Return:

         The number of planes or Nil if the file does not exist or if it is
         not a PCX

    Example:

         ? pcxPlanes ( "c:\fast\lib\fast.pcx" )