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Q149132: BUG: Signed 4-byte Integer Overlow Not Caught by the Compiler

Article: Q149132
Product(s): Microsoft Fortran Compiler
Version(s): 4.0
Operating System(s): 
Keyword(s): kbFortranPS kbLangFortrankbbuglist
Last Modified: 03-NOV-1999

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The information in this article applies to:

- Microsoft Fortran PowerStation for Windows 95 and Windows NT, version 4.0 
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SYMPTOMS
========

The compiler does not catch or reports incorrect information for signed
four-byte integers that are one value greater than the allowable range for these
numerical types. For signed four-byte integers, the allowable range is
-2147483648 to 2147483647.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION
================

In the following sample code, the compiler does not catch and report the literal
value of 2147483648 as an overflow error. When the compiler catches the out of
range literal value of -2147483649, it incorrectly reports it as positive.

Sample Code
-----------

  C Compile options needed: none

        INTEGER*4 MYLONG

        MYLONG =  2147483647    ! OK
        MYLONG =  2147483648    ! out of range - not caught
        MYLONG =  2147483647+1  ! out of range - caught

        MYLONG = -2147483648    ! OK
        MYLONG = -2147483649    ! out of range - caught reported positive
        MYLONG = -2147483648-1  ! out of range - caught

        WRITE(*,*) MYLONG

        END

Additional query words: 4.00

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Keywords          : kbFortranPS kbLangFortran kbbuglist
Technology        : kbAudDeveloper kbPTProdChange kbFortranSearch kbFORTRANPower400NT
Version           : :4.0

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