BUG: READ w/ Numeric Literal Subscript Causes Access Violation

• Microsoft Fortran Powerstation 32 for Windows NT, version 1.0

SYMPTOMS

Exporting an array in a COMMON block from a dynamic-link library (DLL) and attempting to read a member of the array by using a numeric literal as a subscript in the READ statement may generate an access violation.

RESOLUTION

Here are two ways to work around this problem:

• Use INTEGER variables instead of numeric literals as subscripts when accessing COMMON arrays.


-or-


• Read exported COMMON data into local allocatable arrays. Then assign these arrays to the arrays in the exported COMMON block.

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

This error occurs only with READ statements. It does not occur with WRITE statements or when reading COMMON variables.

Sample Code to Reproduce Problem

C  The code for the DLL
C  Compile options needed: /LD
C
       COMMON /TheBlock[DLLEXPORT]/ CommonBlockIntegerArray(3)
       INTEGER*4 CommonBlockIntegerArray
          CommonBlockIntegerArray(1) = 1
          CommonBlockIntegerArray(2) = 2
          CommonBlockIntegerArray(3) = 3
       END
C
C  The code for the EXE.
C  Compile options needed: none
C  Linker options needed: include the import library for the DLL
C
C  Define the common block for sharing.
C
      COMMON /TheBlock[DLLIMPORT]/ CommonBlockIntegerArray(3)
      INTEGER*4 CommonBlockIntegerArray
C
C  Some local variables.
C
      INTEGER*4 intTemp
      CHARACTER*3 someText
C
C  The main program.
C
      someText = '11'
      intTemp = 1
C
C  If the subscript is an integer variable, there is no problem.
C
      READ (someText, '(A3)') CommonBlockIntegerArray(intTemp)
C
C  The array subscript is a numeric literal, an access violation occurs.
C
      READ (someText, '(A3)') CommonBlockIntegerArray(1)
      END 

REFERENCES

For information on a related problem, please see the following article in the Microsoft Knowledge Base:

Q112010 BUG: Access Violation on READ of Exported COMMON Array

Additional query words: 1.00 Dr. Watson imported

Keywords :
Version : :1.0
Platform :
Issue type :