INFO: Caveats for Using Empty Top-Level Projects in Dev. Studio

• The development environment included with: - Microsoft Visual C++, 32-bit Edition, versions 4.0, 4.1, 4.2, 5.0

SUMMARY

This article discusses the process needed to set up a project workspace such that it builds multiple targets that are related. You might want to do this if, for example, you want to set up a workspace to build several related .exe files, and .dll files that they can call. This scenario is described in the Visual C++ User's Guide online documentation in the "Empty Top-Level Project with Multiple Subprojects" section.

The section of the documentation includes a sample scenario where an empty top-level project has two subprojects that build .exe files, and one of the .exe projects has a subproject that builds a DLL. The description of this scenario implies that in general you can set up a top-level project that has no source files, and it implies that the type of the top-level project and the subprojects involved are unimportant; they can be any type. This is not the case. The types of the projects and subprojects involved are important.

MORE INFORMATION

In certain scenarios, you will get the following messages in the output window when you set the default project configuration to the empty top-level project in order to build all the subprojects:

   LINK : warning LNK4001: no object files specified; libraries used
   LINK : error LNK2001: unresolved external symbol _mainCRTStartup
   fatal error LNK1120: 1 unresolved externals
   Error executing link.exe.

If you want to set up a project workspace where the static library or DLL projects are immediate subprojects of an empty top-level project, you need to make the top-level project type be Makefile. In addition, you need to change the build settings for the Makefile project so the "Build command line" setting is blank. In other words, you do not want Developer Studio to invoke any command for the empty top-level project. This will allow you to set up the correct dependency relationship between the top-level project and its subprojects, and it will prevent Developer Studio from attempting to create an output file for the top-level project.

With Visual C++ 5.0 where the DLL projects are immediate subprojects of an empty top-level project, you can select the "Ignore export library" checkbox in the project settings for the DLL subprojects, Link tab, General category. This tells the build system not to automatically link the empty top-level project with the import library generated by the DLL subprojects. This checkbox is not available for static libraries.

Keywords          : VwbIss
Version           : WINNT:4.0,4.1,4.2,5.0;
Platform          : NT WINDOWS
Issue type        : kbinfo