Linker issues compiling example imgui with opengl3 and glfw.

[Cat-Programmer3]

I am pretty sure this is linker issues due to the error messages. I am trying to compile the the example with all the files for glfw + opengl3. I don't have much experience with c++ compiling and I appreciate any help given. (Note: This is a Linux system)

Command: g++ main.cpp -I/home/brandon/Coding/cpp_install/ -L/home/brandon/Coding/cpp_install/libs -lglfw3 -o main

error message:
/usr/bin/ld: /tmp/ccPStiPS.o: in function `main': main.cpp:(.text+0x125): undefined reference to `ImGui::DebugCheckVersionAndDataLayout(char const*, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long)' /usr/bin/ld: main.cpp:(.text+0x133): undefined reference to `ImGui::CreateContext(ImFontAtlas*)' /usr/bin/ld: main.cpp:(.text+0x138): undefined reference to `ImGui::GetIO()' /usr/bin/ld: main.cpp:(.text+0x189): undefined reference to `ImGui::StyleColorsDark(ImGuiStyle*)' /usr/bin/ld: main.cpp:(.text+0x18e): undefined reference to `ImGui::GetStyle()' /usr/bin/ld: main.cpp:(.text+0x1d3): undefined reference to `ImGui_ImplGlfw_InitForOpenGL(GLFWwindow*, bool)' /usr/bin/ld: main.cpp:(.text+0x1df): undefined reference to `ImGui_ImplOpenGL3_Init(char const*)' /usr/bin/ld: main.cpp:(.text+0x249): undefined reference to `ImGui_ImplGlfw_Sleep(int)' /usr/bin/ld: main.cpp:(.text+0x253): undefined reference to `ImGui_ImplOpenGL3_NewFrame()' /usr/bin/ld: main.cpp:(.text+0x258): undefined reference to `ImGui_ImplGlfw_NewFrame()' /usr/bin/ld: main.cpp:(.text+0x25d): undefined reference to `ImGui::NewFrame()' /usr/bin/ld: main.cpp:(.text+0x271): undefined reference to `ImGui::ShowDemoWindow(bool*)' /usr/bin/ld: main.cpp:(.text+0x28a): undefined reference to `ImGui::Begin(char const*, bool*, int)' /usr/bin/ld: main.cpp:(.text+0x29e): undefined reference to `ImGui::Text(char const*, ...)' /usr/bin/ld: main.cpp:(.text+0x2b4): undefined reference to `ImGui::Checkbox(char const*, bool*)' /usr/bin/ld: main.cpp:(.text+0x2ca): undefined reference to `ImGui::Checkbox(char const*, bool*)' /usr/bin/ld: main.cpp:(.text+0x304): undefined reference to `ImGui::SliderFloat(char const*, float*, float, float, char const*, int)' /usr/bin/ld: main.cpp:(.text+0x31f): undefined reference to `ImGui::ColorEdit3(char const*, float*, int)' /usr/bin/ld: main.cpp:(.text+0x34f): undefined reference to `ImGui::Button(char const*, ImVec2 const&)' /usr/bin/ld: main.cpp:(.text+0x379): undefined reference to `ImGui::SameLine(float, float)' /usr/bin/ld: main.cpp:(.text+0x395): undefined reference to `ImGui::Text(char const*, ...)' /usr/bin/ld: main.cpp:(.text+0x3eb): undefined reference to `ImGui::Text(char const*, ...)' /usr/bin/ld: main.cpp:(.text+0x3f0): undefined reference to `ImGui::End()' /usr/bin/ld: main.cpp:(.text+0x413): undefined reference to `ImGui::Begin(char const*, bool*, int)' /usr/bin/ld: main.cpp:(.text+0x427): undefined reference to `ImGui::Text(char const*, ...)' /usr/bin/ld: main.cpp:(.text+0x457): undefined reference to `ImGui::Button(char const*, ImVec2 const&)' /usr/bin/ld: main.cpp:(.text+0x464): undefined reference to `ImGui::End()' /usr/bin/ld: main.cpp:(.text+0x469): undefined reference to `ImGui::Render()' /usr/bin/ld: main.cpp:(.text+0x499): undefined reference to `glViewport' /usr/bin/ld: main.cpp:(.text+0x4de): undefined reference to `glClearColor' /usr/bin/ld: main.cpp:(.text+0x4e8): undefined reference to `glClear' /usr/bin/ld: main.cpp:(.text+0x4ed): undefined reference to `ImGui::GetDrawData()' /usr/bin/ld: main.cpp:(.text+0x4f5): undefined reference to `ImGui_ImplOpenGL3_RenderDrawData(ImDrawData*)' /usr/bin/ld: main.cpp:(.text+0x512): undefined reference to `ImGui::UpdatePlatformWindows()' /usr/bin/ld: main.cpp:(.text+0x521): undefined reference to `ImGui::RenderPlatformWindowsDefault(void*, void*)' /usr/bin/ld: main.cpp:(.text+0x557): undefined reference to `ImGui_ImplOpenGL3_Shutdown()' /usr/bin/ld: main.cpp:(.text+0x55c): undefined reference to `ImGui_ImplGlfw_Shutdown()' /usr/bin/ld: main.cpp:(.text+0x566): undefined reference to `ImGui::DestroyContext(ImGuiContext*)' collect2: error: ld returned 1 exit status

[ocornut]

You are showing a list of files on your filesystem, but they are not part of your compilation process at all. You are only compiling main.cpp.

• You may be able to build all files on the command-line by changing main.cpp to *.cpp, but it will be a little slow because imgui is a bit large. (But it's possible that building main.cpp and imgui_impl_opengl3.cpp in the same compilation unit would fail due to conflicting OpenGL function names).

• More often, people use build systems such as Makefile, Cmake, MSBuild etc which job (in simplified term) is to detect when a .cpp changed, build that .cpp into an object file (.o, .obj), and then link all them into a single program. This has the advantage that you can only rebuild the file that have more recently changed, and it tends to be why people are using build systems.

• Generally, you should be read about building and linking C/C++ applications. Your question is not really specific to dear imgui but to understanding how to build an executable from first principles.

[Cat-Programmer3]

Ok. Will try. Thank you for the response.

[Cat-Programmer3]

I did get my build system with cmake working, thank you for your insights.