Q45892: CALL BYVAL "Parameter Type Mismatch" After DECLARE AS ANY

Article: Q45892
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S890512-58 B_BasicCom buglist4.50 | mspl13_basic
Last Modified: 26-FEB-1990

Using the CALL subprogramname (BYVAL variable) method of calling an
external (non-BASIC) routine, where the parameter is specified AS ANY
in the DECLARE statement, correctly causes a "Parameter Type Mismatch"
at compile time.

To avoid this error, you must add BYVAL and specify the exact type
(instead of using AS ANY) in the DECLARE statement, and you must not
use BYVAL in the CALL statement. This information applies to Microsoft
QuickBASIC Versions 4.00, 4.00b, and 4.50, to Microsoft BASIC Compiler
Versions 6.00 and 6.00b, and to Microsoft BASIC Professional
Development System (PDS) Version 7.00.

Note that the "Parameter Type Mismatch" error fails to be flagged in
the QuickBASIC Version 4.50 environment when the external routine is
in a Quick Library. Microsoft has confirmed this to be a problem in
QuickBASIC Version 4.50. We are researching this problem and will post
new information here as it becomes available. QuickBASIC Versions 4.00
and 4.00b correctly flag the error.

The following is taken from the DECLARE statement documentation in the
BASIC language reference manuals for QuickBASIC Versions 4.00, 4.00b,
and 4.50 and BASIC compiler Versions 6.00 and 6.00b:

   You cannot use ANY [in the DECLARE statement] with arguments
   passed by value.

Code Example
------------

The following code sample should correctly cause a "Parameter Type
Mismatch" error on the CALL statement at compile time (where test is
an external SUB):

   DECLARE SUB test (variable AS ANY)
   i%=10
   CALL test(BYVAL i%)

The following is the correct method to pass by value to the external
procedure:

   DECLARE SUB test (BYVAL variable AS INTEGER)
   i%=10
   CALL test(i%)

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