Synopsis:

       db_handle=db_open(filename,type,mode)

Arguments:

       filename - The full path to the DBF file

       type - Future Use (set to 0)

       mode - Open mode (0=excl,1=shared)

Description:  This function opens the DBF file file specifed by filename.       The type argument is for furture use and should be set to 0.       The mode argument specifies whether the DBF file should be opened in shared or exclusive mode.

If the DBF file is successfully opened then the function returns a file handle to the DBF file otherwise a negative error code is returned.

Returns:   Returns the database handle or a negative error code.