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Q39378: "Formal Parameter Specification Illegal" for DECLARE Variable

Article: Q39378
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom SR# S881208-34 | mspl13_basic
Last Modified: 21-DEC-1988

The BC.EXE compiler generates a "Formal parameter specification
illegal" error when a DECLARE statement uses a variable that is the
same name as a FUNCTION or SUB previously declared in the program.
The QB.EXE editor will not generate an error for the same DECLARE
statement.

In general, you should never have any variables with the same name as
any other identifier in your programs. You should also avoid having
any two variables or identifiers that only differ by the data type
specifier. For example A$ and A% are poor choices for variable names
in the same program.

This information applies to Microsoft QuickBASIC Versions 4.00,
4.00b, and 4.50, and to Microsoft BASIC Compiler Versions 6.00
and 6.00b for MS-DOS and MS OS/2.

The DECLARE statement is only used as a prototype for checking the
number and types of the arguments used to invoke the procedures, and
it affects the entire module. The type of the variables can be
INTEGER, LONG, SINGLE, DOUBLE, STRING, or a user-defined type.
Fixed-length strings (STRING*n) cannot be used in a DECLARE statement,
because only variable-length strings can be passed to SUB and FUNCTION
procedures.

More information about the DECLARE statement can be found in the
"Microsoft QuickBASIC: BASIC Language Reference" manual (on pages
139-146 for QuickBASIC Versions 4.00 and 4.00b; pages 55-56, 271, 299,
and 332- 333 for QuickBASIC Version 4.50; and pages 139-146 for BASIC
Compiler Versions 6.00, and 6.00b).

The following is a code example:

DECLARE FUNCTION test% (Num%)
DECLARE SUB ShowTest (test%)   ' This will generate an error
A = test%(10)
ShowTest (A)
END

SUB ShowTest (Var%)
    PRINT Var%
END SUB

FUNCTION test% (Num%)
    test% = Num%
END FUNCTION

The following error is generated for the above program:

Microsoft (R) QuickBASIC Compiler Version 4.50
(C) Copyright Microsoft Corporation 1982-1988.
All rights reserved.
Simultaneously published in the U.S. and Canada.
 0030   0006    DECLARE SUB ShowTest (test%)
                                      ^ Formal parameter
                                        specification illegal

43869 Bytes Available
43355 Bytes Free

    0 Warning Error(s)
    1 Severe  Error(s)

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