GLEW and GLFW undefined references - c++

Question

I am trying to set up openGl with glfw and glew. This is the source code:
#define GLFW_INCLUDE_GLU
#ifdef _WIN32
#define GLFW_DLL // -> windows
#include <GL/glew.h>
#elif __linux__
#include <GL/glew.h>
#endif
#include <GLFW/glfw3.h>
#include <iostream>
#include <stdexcept>
GLFWwindow* window = NULL;
GLFWmonitor* monitor = NULL;
int window_width = 800;
int window_height = 600;
static void window_hints() {
const GLFWvidmode* mode = glfwGetVideoMode(monitor);
glfwWindowHint(GLFW_RED_BITS, mode->redBits);
glfwWindowHint(GLFW_GREEN_BITS, mode->greenBits);
glfwWindowHint(GLFW_BLUE_BITS, mode->blueBits);
glfwWindowHint(GLFW_REFRESH_RATE, mode->refreshRate);
glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GL_TRUE);
glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GL_TRUE);
}
static void set_window_callbacks() {
glfwSetWindowCloseCallback(window, [] (GLFWwindow *window) {
std::cout << "closing window!";
});
glfwSetKeyCallback(window, [] (GLFWwindow *window, int key,int scancode, int action, int mods) {
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) {
glfwSetWindowShouldClose(window, GLFW_TRUE);
}
});
glfwSetWindowSizeCallback(window, [] (GLFWwindow *window, int width, int height) {
glViewport(0, 0, width, height);
window_width = width;
window_height = height;
glLoadIdentity();
GLdouble aspect = (GLdouble)window_width / window_height;
glOrtho(-1, 1, -1 / aspect, 1 / aspect, 0.01, 10000);
glTranslatef(0, 0, -10);
});
}
void GLAPIENTRY
MessageCallback( GLenum source,
GLenum type,
GLuint id,
GLenum severity,
GLsizei length,
const GLchar* message,
const void* userParam )
{
fprintf( stderr, "GL CALLBACK: %s type = 0x%x, severity = 0x%x, message = %s\n",
( type == GL_DEBUG_TYPE_ERROR ? "** GL ERROR **" : "" ),
type, severity, message );
}
int main(int argc, char *argv[])
{
glfwSetErrorCallback([] (int code, const char * err_msg) {
std::cerr << "GLFW Error " << code << ": \n\t" << err_msg << std::endl;
});
if(!glfwInit())
throw std::runtime_error("glfwInit failed");
monitor = glfwGetPrimaryMonitor();
window_hints();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
window = glfwCreateWindow(window_width, window_height, "test window", NULL, NULL);
if(!window)
throw std::runtime_error("glfwOpenWindow failed.");
set_window_callbacks();
// GLFW settings
glfwMakeContextCurrent(window);
glewInit();
glfwSwapInterval(1);
std::cout << glGetString(GL_VERSION) << std::endl;
glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
glDebugMessageCallback(MessageCallback, 0);
glMatrixMode(GL_PROJECTION);
glViewport(0, 0, window_width, window_height);
glLoadIdentity();
GLdouble aspect = (GLdouble)window_width / window_height;
glOrtho(-1, 1, -1 / aspect, 1 / aspect, 0.01, 10000);
glTranslatef(0, 0, -10);
while(!glfwWindowShouldClose(window))
{
// process pending events
glfwPollEvents();
glClearColor(0, 0, 0, 1); // black
glClear(GL_COLOR_BUFFER_BIT);
//glRotatef(1, 0, 0, 0.1);
glBegin(GL_TRIANGLES);
glColor3f(1.0, 0.0, 0.0);
glVertex2f(-0.5, -0.5);
glColor3f(0.0, 1.0, 0.0);
glVertex2f( 0.5, -0.5);
glColor3f(0.0, 0.0, 1.0);
glVertex2f( 0.0, 0.5);
glEnd();
glfwSwapBuffers(window);
}
// clean up and exit
glfwTerminate();
std::cerr << std::endl;
return 0;
}
And this works perfectly under Linux with the following makefile:
main: main.cpp makefile
g++ main.cpp -g -o main -lglfw -lGL -lX11 -lGLEW -std=c++2a
Then, I wanted to make it to compile under windows too, so I tried with this makefile:
main.exe: main.cpp makefile
g++ main.cpp -g -o main.exe -I"D:\cpp_libraries\glfw-3.3.5.bin.WIN64\include" -I"D:\cpp_libraries\glew-2.1.0\include" -L"D:\cpp_libraries\glfw-3.3.5.bin.WIN64\lib-mingw-w64" -L"D:\cpp_libraries\glew-2.1.0\lib\Release\x64" -lglfw3dll -lglew32 -lopengl32
Here, "glew-2.1.0" and "glfw-3.3.5.bin.WIN64" are downloaded from the respective download pages for precompiled windows binaries. I have added "D:\cpp_libraries\glew-2.1.0\bin\Release\x64" and "D:\cpp_libraries\glfw-3.3.5.bin.WIN64\lib-mingw-w64" to the Path environment variable as they contain glew32.dll and glfw3.dll.
When I try to compile, g++ gives "undefined reference to " every single glew/gl/glfw function call. I also tried running the same g++ command through VS Code's tasks.json with the same result.
Then I noticed that everyone on the internet said I must link against "glfw3.lib" and I noticed that the first -L argument to g++ is a folder that does not actually contain any .lib files as it should. But I cannot find the "glfw3.lib" anywhere in the zip I downloaded earlier. I even tried building glfw from source with CMake, Make and Code::Blocks, but none of them generated a .lib file I can link against.
Edit: I forgot to mention that I have not added the dlls to my project directory, but it really should not be necessary. I tried it anyway and it didn't fix the problem.
Edit 2: it would be better to link with -lglfw, not -lglfwdll, so I changed that.
Edit 3: actually, gl functions are getting linked fine. The problem is only with glfw and glew.

Answer 1

I finally got it working. It turns out the precompiled binaries for glew and glfw do not work on my machine. I had to download both sources and compile the libraries myself. This is the makefile that finally works:
main.exe: main.cpp makefile
g++ main.cpp -g -o main.exe -I"D:/cpp_libraries/glfw-3.3.5-source/include" -I"D:/cpp_libraries/glew-2.1.0-source/include" -L"D:/cpp_libraries/glfw-3.3.5-compiled/src" -L"D:/cpp_libraries/glew-2.1.0-compiled/lib" -lglfw3 -lglew32 -lopengl32