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Q28981: Compiled with BC, SHARED Long Integer Arrays Are Wrong in SUB

Article: Q28981
Product(s): See article
Version(s): 4.00 4.00b
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom buglist4.00 buglist4.00b fixlist4.50 | mspl13_basic
Last Modified: 31-JAN-1990

In the programs below, which are compiled with BC /o/d or BC, using
SHARED long integer arrays in a subprogram causes variables or array
elements to be set at zero (0) or incorrect negative values.

Microsoft has confirmed this to be a problem in QuickBASIC Versions
4.00 and 4.00b, and in Microsoft BASIC Compiler Versions 6.00 and
6.00b for MS-DOS and OS/2 (buglist6.00, buglist6.00b). This problem
was corrected in QuickBASIC Version 4.50 and in Microsoft BASIC
Professional Development System (PDS) Version 7.00 for MS-DOS and MS
OS/2 (fixlist7.00).

You can work around this problem by placing line numbers in the
program.

Note: This problem does not occur in QuickBASIC Versions 1.x, 2.x, and
3.x because these versions do not support long integers.

The following two programs demonstrate this problem:

Example 1
---------

DECLARE SUB tvf (j%, tm$, w&)  'Order of arguments does not alter results.
DEFLNG T
'Declaring the array to be $STATIC or $DYNAMIC makes no difference.
DIM SHARED te6(2), te5(2), te4(2), te2(2)
te2(2) = 100&: te4(2) = 10000&: te5(2) = 100000: te6(2) = 1000000
DO
  PRINT "Enter up to 8 digits"
  LINE INPUT a$
  CALL tvf(2, a$, w&)            'If the 2 is not passed, then it works.
  PRINT "Value of that is "; w&
  LOOP UNTIL a$ = ""
END

SUB tvf (j%, tm$, w&) STATIC            'Same problems if this is a function.
    PRINT te6(j%), te5(j%), te4(j%), te2(j%)     'This line always prints OK.
    q$ = RIGHT$("00000000" + tm$, 8)
    t = VAL(MID$(q$, 1, 2)) * te6(j%)  'If these lines are divided up, it
    t = t + VAL(MID$(q$, 3, 1)) * te5(j%)  'makes no difference, but if there
    t = t + VAL(MID$(q$, 4, 1)) * te4(j%)  'are line numbers on these lines,
    t = t + VAL(MID$(q$, 5, 2)) * te2(j%)  'IT WILL WORK!
    PRINT te6(j%), te5(j%), te4(j%), te2(j%)
    w& = t + VAL(MID$(q$, 7, 2))
END SUB

Example 2
---------

'-------The program includes 1 subprogram
DECLARE SUB logtran (ntn!)
OPTION BASE 1
COMMON SHARED cashp&, D&(), cash$, d1$
DIM d&(1)
OPEN "dt.dat" FOR RANDOM AS #1
FIELD #1, 8 AS cash$, 4 AS d1$
d&(1)=0
cashp& = 0
ntn! =1
CALL logtran (ntn!)
END

SUB logtran (ntn!) STATIC
PRINT "ntn!:";ntn!
LSET cash$ = MKD$(CDBL(cashp&))
PRINT "ntn!:";ntn!
LSET d1$=MKS$(CSNG(d&(1)))
PRINT "ntn!";ntn!
CLOSE
END SUB

Output for the example 2:

ntn! 1
ntn! 1
ntn! -5.965761E-30

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