Linking against a library that links against other libraries

[Epsylene]

I am trying to write a premake file for an app that links against a custom library, which in turn links against GLFW. The test premake file looks like this:

workspace "HelloWorld"
    configurations { "Debug", "Release" }

project "Lib"
    kind "SharedLib"
    language "C++"
    targetdir "bin"

    files { "src/**.h", "src/**.cpp" }

    includedirs "vendor/glfw/include"
    libdirs "vendor/glfw/lib"
    links { "glfw3", "opengl32" }

project "App"
    kind "ConsoleApp"
    language "C++"
    targetdir "bin"
    staticruntime "On"

    files { "app/**.h", "app/**.cpp" }

    includedirs { "src", "vendor/glfw/include" }

    libdirs "vendor/glfw/lib"
    links { "Lib", "glfw3", "gdi32" }

The library directory contains a single file with a function that calls some GLFW test code, and the app is comprised of a single file that calls this function; here is a ZIP file containing them both. GLFW was pre-built as a static library here.

The problem is that if I don't link App against glfw3 and gdi32, I get a bunch of "undefined reference" errors from GLFW and libgdi32. I don't understand why this is, even though I am linking against my library, which links against those libraries; since my library DLL is placed along my executable in the bin directory, there should be no problem, right ? If possible, I would like to allow users of my library to only have to link against my library, without caring about its dependencies (is this realistic ? I still lack a lot of understanding when it comes to linking and managing libraries and their dependencies).

Excuse me if this is not the right place to ask these kind of questions, I couldn't find (or understand) a clear answer to this problem elsewhere.

[samsinsane]

Your Lib library doesn't contain any code - functions in headers like hello.h aren't compiled in the library but in the file that #includes them, in this case app.cpp. You need to put the contents of notmain() into hello.cpp and then export it like this:

// Windows
__declspec(dllexport) int notmain();

// Not-Windows
__attribute__((visibility("default"))) int notmain();

You can see how GLFW does it here and it is used here.

[Epsylene]

I see, thanks for the reply !