OpenGLES • Hello Triangle - Compiles and runs, but no triangle

Code:

gcc -o ogl3_min ogl3_min.c -lGL -lGLU -lglut -lGLEW

Code:

#include <GL/glew.h>#include <GL/glut.h>#include <stdio.h>GLuint program;const GLchar* vertexShaderSource = "#version 300 es\n"    "in vec2 position;\n"    "void main()\n"    "{\n"    "    gl_Position = vec4(position, 0.0, 1.0);\n"    "}\0";const GLchar* fragmentShaderSource = "#version 300 es\n"    "precision mediump float;\n"    "out vec4 FragColor;\n"    "void main()\n"    "{\n"    "    FragColor = vec4(1.0, 0.0, 0.0, 1.0);\n"    "}\0";int init() {    GLuint vertexShader, fragmentShader;    vertexShader = glCreateShader(GL_VERTEX_SHADER);    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);    glCompileShader(vertexShader);    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);    glCompileShader(fragmentShader);    program = glCreateProgram();    glAttachShader(program, vertexShader);    glAttachShader(program, fragmentShader);    glLinkProgram(program);    glDeleteShader(vertexShader);    glDeleteShader(fragmentShader);    glUseProgram(program);    return 1;}void display() {    glClear(GL_COLOR_BUFFER_BIT);    glDrawArrays(GL_TRIANGLES, 0, 3);    glutSwapBuffers();}void initGL() {    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);}void reshape(int w, int h) {    glViewport(0, 0, w, h);}int main(int argc, char** argv) {    glutInit(&argc, argv);    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);    glutInitWindowSize(800, 600);    glutCreateWindow("Simple Shader");    glutDisplayFunc(display);    glutReshapeFunc(reshape);    glewExperimental = GL_TRUE;    glewInit();    initGL();    init();    glutMainLoop();    return 0;}