R_IsRCmp() 
 Determines if a file has been compressed by R_Compress()
------------------------------------------------------------------------------

 Syntax
        lCompressed := R_IsRCmp ( cInFile )

 Arguments
        cInFile         File specification of the file to be examined
                        Format  : [drive:][\path\]filename[.ext]
                        Example : C:\INVOICE\INVOICE.DBF

 Returns
        lCompressed     .T. : file IS compressed by R_Compress()
                        .F. : file IS NOT compressed by R_Compress()
                              -OR- error occurred while executing R_IsCmp()
                              (p.e. the input file doesn't exist)
                              The error can be examined using the
                              R_LastErr () function.

 Description
        Determines if a file has been compressed using the R_Compress()
        function.
        Using this function it is easy to determine which files in a
        particular directory are compressed by R_Compress() and so can
        be decompressed using the R_DeComp() function.

 Example
        *-- Decompressed all compressed file in the current directory

        #include "Directry.CH"

        AEval ( Directory ( '*.*' ), ;
                { |aFile| IF ( R_IsRCmp ( aFile [F_NAME] ), ;
                               R_DeComp ( aFile [F_NAME] ), ;
                               nil ;
                             ) ;
                 } ;
              )

        See also the demo program RCmpDemo.PRG