BUG: Watching a DLL Common Block Using Context Operator Fails

• Microsoft Fortran PowerStation for Windows 95 and Windows NT, version 4.0

SYMPTOMS

Attempting to view a DLL variable or common block contents in a watch window using the context operator {} fails with the following messages:

DLL variable:

"EE2347: Undefined variable"

"Invalid Debug Information"

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

Debug information for DLL variables and common blocks is available in the debugger's Locals window. The members of a common block can be viewed in a watch window but only if specified without the context operator. Trying to view a DLL variable or common block by using the context operator will always fail. Also, attempting to watch a common block structure in a watch window will fail with the message "Invalid Debug Information".

Steps to Reproduce Problem

1. Create two source code files using the sample code provided. One (Theapp.for) will be the main source code and the other (Thedll.for) will be the DLL source code.



2. Create a QuickWin project using the main source file (Theapp.for). From the Developer Studio File menu, choose New, and then double-click the Project Workspace option. In the New Project Workspace dialog box, click the QuickWin Application type, name the project TheApp, set the project directory, and click the Create button.



3. Insert the main source code file into the project. From the Insert menu, choose Files into Project. and select the Theapp.for file.



4. Create a DLL project using the file Thedll.for, which will be a subproject of the QuickWin project created in step 2. From the Insert menu, choose Project, and then in the Insert Project dialog box, click the Dynamic-Link Library type, name the project TheDll, click Subprojects of:, and click the Create button.



5. Insert the DLL source code file into the subproject. From the Insert menu, choose Files into Project, and select the Thedll.for file.



6. Set the DLL build output directory to be the same as the QuickWin build output directory. From the Build menu, choose Settings, and then select the General folder tab. In the Settings For list box, highlight the DLL debug project target "TheDll - Win32 Debug (TheDll.dll)." Then select the Output files edit box, and remove the "TheDll\Debug" text, replacing it with "Debug." Then click the OK button to save the changes and exit the dialog box.



7. Build and link the QuickWin and DLL projects. In Developer Studio, change the default configuration to "TheApp - Win32 Debug." Then from the Build menu, choose Rebuild All.



8. Try to view the common block or its members in a watch window. Begin a debugging session, from the Build menu, choose Debug, and then select Step Into. Step past the variable initialization statements in the DLL. Now, in a watch window, type the variable "i" or the common block name "TheBlock" using the context operator as in the following examples and press the ENTER key.

   Example One

   Type:

   {,,TheDll.dll}i

   Result:

   This fails with "EE2347: Undefined variable"

   Example Two

   Type:

   {,,TheDll.dll}TheBlock

   Result:

   This fails with "Invalid Debug Information"

Sample Code

Main

C Compile options needed: /MW /Zi
C TheApp.for (QuickWin app)
      program TheApp
          integer i, j
          common /TheBlock/ i, j
          !ms$attributes dllimport :: TheBlock
          call initcommon()
          print *, i, j
      end 

DLL

C Compile options needed: /LD /Zi
C TheDll.for (DLL for TheApp)
      subroutine initcommon()
          !ms$attributes dllexport :: initcommon
          integer i, j
          common /TheBlock/ i, j
          !ms$attributes dllexport :: TheBlock
          i = 5
          j = 7
      end 

Additional query words: 4.00

Keywords : kbDebug kbide
Version : :4.0
Platform : NT WINDOWS
Issue type :