Q58022: QB.EXE Variable Is Wrongly Global If Name Same as COMMON Array

Article: Q58022
Product(s): See article
Version(s): 4.00 4.00b
Operating System(s): MS-DOS
Keyword(s): ENDUSER | buglist4.00 buglist4.00b fixlist4.50 SR# S900110-109 | mspl13_basic
Last Modified: 7-FEB-1990

Naming a variable the same as an array in COMMON incorrectly makes the
variable global in the following program when run in the QB.EXE
environment of QuickBASIC Version 4.00 or 4.00b.

Microsoft has confirmed this to be a problem in QuickBASIC Versions
4.00 and 4.00b. This problem was corrected in QuickBASIC Version 4.50.

To work around this problem, you can either upgrade to Version 4.50 or
compile the program to an .EXE with BC.EXE.

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

The value of the variable "test2" incorrectly changes when the
function "test" is called. This behavior is incorrect because the
variable in the main program is not SHARED, and therefore, the test2
variable in the function should be kept separate from the one in the
main module. The problem is related to passing an array, test2(), in
the COMMON SHARED statement that has the same name as the variable,
test2.

  DEFDBL T
  DECLARE FUNCTION test (temp%)
  DIM test2(100)
  COMMON SHARED test2()
    test2 = 1.299933
    CLS
    PRINT "Before Test Test2 = "; test2
    res = test(10)
    PRINT "After Test Test2 = "; test2
 END

FUNCTION test (temp%)
    PRINT "Test2 = "; test2
    test2 = 3.999
    PRINT "Test2 =  "; test2
    test = test2
END FUNCTION

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