Q60131: Problem with MID$ Statement and MID$ Function in QBX.EXE

Article: Q60131
Product(s): See article
Version(s): 7.00 7.10
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S900315-77 buglist7.00 buglist7.10 | mspl13_basic
Last Modified: 20-SEP-1990

Using the MID$ function as an argument of the MID$ statement can
produce incorrect results in the QBX.EXE environment that comes with
Microsoft BASIC Professional Development System (PDS) versions 7.00
and 7.10, as shown in the program below.

The problem does not occur when compiled with the BC.EXE environment
of Microsoft BASIC PDS 7.00 and 7.10; with the BC.EXE or QB.EXE
environment of Microsoft QuickBASIC version 4.00, 4.00b, or 4.50; or
with the BC.EXE or QB.EXE environment of Microsoft BASIC Compiler
versions 6.00 and 6.00b.

Microsoft has confirmed this to be a problem in the QBX.EXE
environment of Microsoft BASIC PDS versions 7.00 and 7.10. We are
researching this problem and will post new information here as it
becomes available.

The program below should correctly output "1212345678". However, when
run from within the QBX.EXE environment, it incorrectly outputs
"1212121212". This behavior also occurs if a length% argument of 10 is
used in the MID$ function. If 8 or 9 is used as the length% argument
of the MID$ function, the correct output is produced. If the start%
argument of the MID$ function is not taken to be 1, correct output
displays.

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

   A$= "1234567890"
   MID$(A$, 3) = MID$(A$, 1)
   PRINT A$

Note: The first MID$ occurrence above is the MID$ statement, and the
second occurrence is the MID$ function.

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