Q46180: STATIC FUNCTION Fails to Retain Value Between Invocations
Article: Q46180 Product(s): See article Version(s): 4.00 4.00b 4.50 Operating System(s): MS-DOS Keyword(s): ENDUSER | buglist4.00 buglist4.00b buglist4.50 B_BasicCom | mspl13_basic Last Modified: 20-SEP-1990 A function that has been declared with the STATIC attribute should retain its value between calls. When a STATIC function is called and assigned a value, subsequent calls to the function that do not assign a new value to the function should always return the previous value, even if you leave the function with an EXIT FUNCTION statement. This behavior is correctly exhibited by programs compiled with BC.EXE. However, when you attempt the same procedure in the QB.EXE or QBX.EXE environment, a STATIC FUNCTION fails to retain its value in multiple invocations, and incorrectly returns a 0 (zero) or null string, depending on the type of the function. Microsoft has confirmed this to be a problem in the QB.EXE environment of Microsoft QuickBASIC versions 4.00, 4.00b, and 4.50; in the QB.EXE environment of Microsoft BASIC Compiler versions 6.00 and 6.00b (buglist6.00, buglist6.00b); and in the QBX.EXE environment of Microsoft BASIC Professional Development System (PDS) versions 7.00 and 7.10 (buglist7.00, buglist7.10). We are researching this problem and will post new information here as it becomes available. The following sample program demonstrates the problem: x% = staticfun%(1) PRINT x% ' Should print 5. x% = staticfun%(0) PRINT x% ' Should print 5. END FUNCTION staticfun%(parm%) STATIC IF parm% = 0 THEN EXIT FUNCTION ELSE staticfun% = 5 END IF END FUNCTION When this program is compiled with BC.EXE, it correctly prints the values 5 and 5. From inside the QuickBASIC QB.EXE or QBX.EXE environment, it incorrectly prints 5 and 0.
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