Problem with static library in C++

Question

Hi all,

I'm trying to use a static library created by me in Visual C++ 2005 (unmanaged C++). I declare one function "int myF(int a);" into a .h file, I implement it in a .cpp file, I compile it - the .lib file is produced.

I create a new project (a separate solution) in VC++ 2005 (also native C++), I add the paths for the include file and the lib file; when I invoke the function myF the linker reports an error: "error LNK2019: unresolved external symbol _myF referenced in function _main". if I create the client project in the same solution as the library project and then add a reference to the library projects, it works, but I'm not going to implement everything like this, but rather to add external libraries to my projects...

What is wrong?

Thank you.

Answer 1

Try setting additional dependencies in the linker input for a project properties.

Answer 2

You need to also include the actual .lib file in your 2nd project (not just the path to it).

There should be an option in the linker settings to do this.

Answer 3

It is not sufficient to list the folder in which MyStatic.lib can be found. You have to explicitly tell the linker that Dependant.vcproj is using MyStatic.lib.

In VS2005 you do this by project properties->Linker->Input->Additional Dependencies. You can also sprinkle some preprosessor stuff in the .h file to tell the compiler to tell the linker to use MyStatic.lib.

Edit: The preprocessor magic goes like this

#pragma comment(lib, "MyStatic.lib")

Answer 4

(EDIT: This was a response to the question of getting the /NODEFAULTLIB error in link phase which has now been deleted... shrug)

You are mixing compiler settings if your are getting the defaultlib error. For example, if you build your library in debug and the build your main in release, you will get this error since they are built to use different versions of the CRTL. This can also happen if you use different settings for linking with the C Runtime as a object library or as a DLL. (See the C/C++ options, the "Code Generation" section, under the "Runtime Library" setting)

In many projects there isn't much you can do if you can't correct the settings of the library (for example, 3rd party libraries). In those cases you have to use the /NODEFAULTLIB switch which is a linker option in the "Input" section called "Ignore Specific Library".

But since you are in control of both the main and the library, build a debug and a release version of your LIB file or make sure your "C/C++;Code Generation;Runtime Library" settings match in both projects.