PRB: Error Converting Visual C++ OLE Controls from 2.x to 4.0

• Microsoft Visual C++, 32-bit Edition, versions 2.0, 2.1, 2.2, 4.0
• Microsoft OLE Control Developer's Kit (CDK)

SYMPTOMS

When you use the following procedure to convert a project built with the CDK that shipped with Visual C++ 2.x to Visual C++ 4.0, the following error appears:

   Linking...
   LINK : fatal error LNK1104: cannot open file "ocs30d.lib"
   Error executing link.exe.
   circ1.ocx - 1 error(s), 0 warning(s)

Conversion Procedure

1. On the File menu, click Open Workspace.

2. Browse to the project directory.

3. List files of type *.mak.

4. Select the 32-bit project file.

5. Click Rebuild All. After it tries to link, the following error message will appear:

   Linking... LINK : fatal error LNK1104: cannot open file "ocs30d.lib" Error executing link.exe. circ1.ocx - 1 error(s), 0 warning(s)

   The actual .lib file that is displayed will be one of four variants of the Ocs30*.lib file depending on how the project is being built.

CAUSE

The reason that the specified file cannot be found is that it no longer exists in Visual C++ version 4.0. Because the Ocs30* libraries were variants of the MFC libraries, the functionality was merged with the Mfc40*.dll. This had several advantages, including better code reuse as one MFC .dll file can be used for both the OLE Control container and the OLE control. The problem is that the ocs30*.lib file is included within the Settings, Link page thereby giving the error Ocs30*.lib cannot be found.

RESOLUTION

Change the settings so that Visual C++ version 4.0 is no longer trying to link in the Ocs30*.lib file. This can be done by following these steps:

1. On the Build menu, click Settings, and then click the Link tab.

2. Click the first of the four project build options under Settings For.

3. Delete Ocs30d.lib from the edit field under Object/Library Modules.

4. Click each of the other three project build options and repeat step 3.

STATUS

This behavior is by design.

MORE INFORMATION

Sample Code

   /* Compile options needed:
   */