Q27490: FUNCTION Fails to Return Zero by Default When Compiled as .EXE

Article: Q27490
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom buglist4.00 buglist4.00b buglist4.50 | mspl13_basic
Last Modified: 20-SEP-1990

When a FUNCTION is called multiple times inside the QB.EXE editor, the
FUNCTION automatically returns a value of (0) zero unless it is set to
some other value within the FUNCTION, as expected.

However, when run from an .EXE file, the value returned by a FUNCTION
is no longer reset to zero by default; it retains its value from the
previous invocation.

Microsoft has confirmed this to be a problem in QuickBASIC versions
4.00, 4.00b, and 4.50 for MS-DOS; in Microsoft BASIC Compiler versions
6.00 and 6.00b for MS-DOS and OS/2 (buglist6.00, buglist6.00b); and in
Microsoft BASIC Professional Development System (PDS) versions 7.00
and 7.10 (buglist7.00, buglist7.10) for MS-DOS and MS OS/2. We are
researching this problem and will report new information here as it
becomes available.

When running the program below in the QB.EXE or QBX.EXE editor, the
first five FUNCTION calls return a value of 99; the next five, from
i%=6 to 10, return zeros, as expected. However, when run as an .EXE
program, the last five FUNCTION calls incorrectly return a value of
99 instead of zero.

To work around the problem, add the line "fun%=0" as the first line of
the function; the .EXE file will then work properly.

The following a code example demonstrates the problem when compiled
with BC.EXE, linked, and run as an .EXE program:

   DECLARE FUNCTION fun% (i%)
   FOR i% = 1 TO 10
     PRINT fun%(i%)
   NEXT i%
   FUNCTION fun% (i%) STATIC
     ' fun%=0   ' This line can be added as a workaround.
   IF i% <= 5 THEN fun% = 99
   END FUNCTION

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