pcxIsPCX()

         Indicates if a file has PCX format or not

    Syntax:

         pcxIsPCX ( cFile ) -> lEsPCX

         cFile : Name of the PCX file

    Description:

         This function returns a logic indicating if the file is PCX or not.
         The rest of the PCX functions uses this one to determine when to
         return a value.

    Return:

         .T. if the file is a PCX or .F. if it does not have PCX format or
         does not exist.

    Example:

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