When building my application or dll, I get error LNK1104: cannot open file 'xxx.lib' or error C1083: ‘cannot open include file xxx.h’

  This is caused by the fact that the linker or compiler cannot find the specified file. Make sure the linker or compiler knows where to look.

Explanation

By default, the build tools will only look for include files and lib files (*) in the current working directory.

If the specified file is not found, the tool will look for the file in any alternate locations that have been configured. If it is still not found in one of those locations, it will report an error.

These alternate locations can be configured in 2 ways.

The first option is to make these locations global to your visual studio options. This has the advantage that you only have to configure it once. The disadvantage is that you have to remember to reconfigure this setting if you want to build your project on another computer.

The second option is to configure this in your project settings. This has the advantage that you can build your project on all development computers that have the appropriate SDKs installed at the same location. The disadvantage is that you have to reconfigure this setting for each new project and configuration, unless you make these settings part of a custom project template.

One common way to configure your system is to add folders to the global visual studio settings if you use them nearly always (for example the Platform SDK), and add them to your project settings if they are specific to that project.

To configure this in Visual C++ 6

• Include files:

  Under Project settings on the C++ tab, select the ‘preprocessor’ category and add the folder to ‘additional include directories’

  Or

  Under tools-> options select the ‘directories’ tab, select ‘include files’ in the drop down box and add the path to the listbox of include files.

• Library files:

  Under Project settings on the link tab, select the ‘input’ category and add the folder to ‘additional library path’

  Or

  Under tools-> options select the ‘directories’ tab, select ‘library files’ in the drop down box and add the path to the listbox of include files.

To configure this in Visual C++ 2003 / Visual C++ 2005

• Include files:

  Under Project settings, on the Configuration properties->C++->general tab, add the folder to ‘additional include directories’

  Or

  Under tools-> options select the Projects->VC++ directories tab, select ‘include files’ in the drop down box and add the path to the listbox of include files.

• Library files:

  Under Project settings, on the Configuration properties->linker->general tab, add the folder to ‘additional library directories’

  Or

  Under tools-> options select the Projects->VC++ directories tab, select ‘include files’ in the drop down box and add the path to the listbox of include files.

(*)

If your project uses library files that are generated by another project in the same solution, you can automatically add that library to your linker input by making your project dependent on the project that generates the library file.

There are 2 caveats however:

• A lib file will only be generated if the dll contains unmanaged exported symbols. If it doesn’t, then no lib file will be generated. The application that depends on the dll will still expect the lib file however. This can also lead to linker error LNK1104.
• If the dll is compiled with /clr, a lib file will still be generated if there are unmanaged exports, but it will not automatically be used by the project that depends upon it, even if the project flag ‘link library dependencies’ is set. In that case you have to manually add it to your linker input, because visual studio doesn’t do it.
• If you specify the /clr switch for the dll, the assumption that it should contain unmanaged exports is no longer valid. It could just as well be a classlib. In that case (no native exports) there will be no lib file because there are no import directives to generate. If there is no lib file, the build of your app would fail with LNK1104 if it would expect the lib file to be there.
• Visual C++ ignores the import libraries of dlls that were compiled with /clr when it examines the project dependencies. This is not documented in MSDN, but it is confirmed by Microsoft in the product feedback center on the following page: http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=109979

Acknowledgements

This FAQ was contributed by Bruno van Dooren.