I am trying to make a purple window with glfw and bgfx as just a starting point for my game engine but the file wont compile.

I am using the g++ compiler for it. I just learning bgfx since yesterday and don't know what to do. The compiler statement is:

g++ app.cpp -o src/app -lglfw3 -lGL -lX11 -lGLU

and my code is

    #include <bgfx_engine/containers/include/bgfx/bgfx.h>
    #include <bgfx_engine/containers/include/bgfx/platform.h>
    #include <GLFW/glfw3.h>
    #define GLFW_EXPOSE_NATIVE_X11
    #include <GLFW/glfw3native.h>

    #define WNDW_WIDTH 1600
    #define WNDW_HEIGHT 900

    int main(void)
    {
    bgfx::init();
    glfwInit();
    GLFWwindow* window = glfwCreateWindow(WNDW_WIDTH, WNDW_HEIGHT, "Hello, bgfx!",NULL ,NULL)                   
    bgfx::PlatformData pd;
    pd.ndt = glfwGetX11Display();
    pd.nwh = (void*)glfwGetX11Window(window);

    bgfx::Init bgfxInit;
    bgfxInit.type = bgfx::RendererType::Count ;//auto choose a renderer
    bgfxInit.resolution.width = WNDW_WIDTH;
    bgfxInit.resolution.height = WNDW_HEIGHT;
    bgfxInit.resolution.reset = BGFX_RESET_VSYNC;
    bgfx::init(bgfxInit);
    bgfx::setViewClear(0,BGFX_CLEAR_COLOR | BGFX_CLEAR_DEPTH,0x443355FF,1.0f,0);
    bgfx::setViewRect(0, 0, 0, WNDW_WIDTH, WNDW_HEIGHT);

    unsigned int counter = 0;
    while (true) 
    {
        bgfx::frame();
        counter++;
    }
    

    return 0;
}

and it shows the error:

/usr/bin/ld: /tmp/ccQWzYSO.o: in function `main':
app.cpp:(.text+0x16): undefined reference to `bgfx::Init::Init()'
/usr/bin/ld: app.cpp:(.text+0x25): undefined reference to `bgfx::init(bgfx::Init const&)'
/usr/bin/ld: app.cpp:(.text+0x5c): undefined reference to `bgfx::PlatformData::PlatformData()'
/usr/bin/ld: app.cpp:(.text+0x8a): undefined reference to `bgfx::Init::Init()'
/usr/bin/ld: app.cpp:(.text+0xc1): undefined reference to `bgfx::init(bgfx::Init const&)'
/usr/bin/ld: app.cpp:(.text+0xe4): undefined reference to `bgfx::setViewClear(unsigned short, unsigned short, unsigned int, float, unsigned char)'
/usr/bin/ld: app.cpp:(.text+0x103): undefined reference to `bgfx::setViewRect(unsigned short, unsigned short, unsigned short, unsigned short, unsigned short)'
/usr/bin/ld: app.cpp:(.text+0x114): undefined reference to `bgfx::frame(bool)'
collect2: error: ld returned 1 exit status

thank you