R_RPCXInfo() 
 Gets information of a specific PCX-file
------------------------------------------------------------------------------

 Syntax
        nRet := R_PCXInfo ( cPCXFile, @nWidth, @nHeight, @nColours, @nAdapter )

 Parameters
        cPCXFile        Filespec of the PCX-file to be examined
                        Format  : [drive:][\path\]filename.PCX
                        Example : C:\PICTURES\TREE.PCX
                        The extension (.PCX) may not be omitted !

        @nWidth         Variable (BY REFERENCE !) to which the WIDTH of the
                        picture is returned

        @nHeight        Variable (BY REFERENCE !) to which the HEIGHT of the
                        picture is returned

        @nColours       Variable (BY REFERENCE !) to which the
                        NUMBER OF COLOURS of the picture is returned
                        (16 or 256)

        @nAdapter       Variable (BY REFERENCE !) to which the CODE of the
                        REQUIRED ADAPTER is returned

                        These codes are defined in RPCXLib.CH :

                        1 = PL_EGA      EGA adapter required
                        2 = PL_VGA      Standard VGA adapter required
                        3 = PL_SVGA     SuperVGA adapter required

 Returns
        nRet            Return code of R_PCXInfo()

                        The values and descriptions of this return code are
                        defined in RPCXLib.CH :

                        0 = PL_OKAY                     Okay
                        1 = PL_INVALID_PARAMETER        Invalid parameter
                                                        passed
                        2 = PL_OPEN_PCX                 Error opening PCX-file
                        3 = PL_READ_PCX                 Error reading PCX-file
                        4 = PL_NO_PCXFILE               File is no valid
                                                        PCX-file
                        5 = PL_INVALID_BPP              Invalid number of
                                                        Bits-Per-Pixel

 Description
        Using the R_PCXInfo() function makes it possible to get information
        about a PCX-file before displaying it.
        For example you can see what kind of graphic adapter is needed
        to display the specific picture.

 Example
        See PCXDemo.PRG