Somehow this code is not working. I don't know why and I also don't get any OpenGL errors.

#define GLEW_STATIC
#include <GL\glew.h>
#include <GLFW\glfw3.h>
#include <GL\glew.h>
#include <glm.hpp>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
 
#define WIDTH 800
#define HEIGHT 600
#define TITLE "Dynamic"
 
GLFWwindow* window;
int vaoID;
 
 
float vertices[] = {-0.5f, 0.5f, 0, -0.5f, -0.5f, 0, 0.5f, -0.5f, 0, 0,};
GLushort indices[] = { 0, 1, 2};
 
void update() {
GLuint vertexBuffer;
GLuint indexBuffer;
GLuint vao;
glGenBuffers(1, &vertexBuffer);
glGenBuffers(1, &indexBuffer);
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);
glEnableVertexAttribArray(0);
while (!glfwWindowShouldClose(window)) {
glfwPollEvents();
glClear(GL_COLOR_BUFFER_BIT);
glClearColor(1, 0, 0, 1);
glfwSwapBuffers(window);
glDrawElements(GL_TRIANGLES, sizeof(indices), GL_UNSIGNED_SHORT, nullptr);
std::cout << glGetError() << std::endl;
}
}
 
int main() {
if (!glfwInit())
std::cout << "Couldn't initialize GLFW!" << std::endl;
 
window = glfwCreateWindow(WIDTH, HEIGHT, TITLE, NULL, NULL);
glfwMakeContextCurrent(window);
glfwSwapInterval(1);
 
if (GLEW_OK != glewInit())
std::cout << "GLEW is not working!" << std::endl;
 
std::cout << "Your GL version: " << glGetString(GL_VERSION) << std::endl;
//glEnable(GL_CULL_FACE);
//glCullFace(GL_BACK);
update();
}

You're drawing the triangle after you have swapped the back and front buffers. You need to first clear, then draw, and then swap the buffers.

You're drawing the triangle after you have swapped the back and front buffers. You need to first clear, then draw, and then swap the buffers.

Thank you, now it is working!