FILECHECK()
 Calculates/computes/determines a checksum for a file
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 Syntax

     FILECHECK(<cFile>) --> nCheckSum

 Argument

     <cFile>  Designates which file name (with path, if required), to
     check.

 Returns

     FILECHECK() returns a checksum value for <cFile>.

 Description

     FILECHECK() determines if there have been changes or read errors in a
     file, and then takes note of data backup.  This also allows you to
     protect your hard disk from simple viruses (see Examples).

 Note

     .  You must specify the argument.  If it is omitted or an
        unavailable file is specified, FILECHECK() returns an error code of -
        1.  You may use a drive and access path, but no wildcards.

 Examples

     .  Check database for changes:

        IF FILECHECK("CUST.DBF") <> Old_ChkSum
           ? "Warning! Data back-up required."
        ENDIF

     .  Check COMMAND.COM for changes:

        IF FILECHECK("\COMMAND.COM") <> Cmd_ChkSum
           ? "COMMAND.COM has been changed! Caution, Virus!"
        ENDIF