# OpenGL GL_ARB_vertex_buffer_object extension : crash at runtime

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Hi, I can compile and link the following very simple code but it's crashing at runtime. #include <GL/glew.h> int main(int argc,char **argv) { GLuint id; glGenBuffers(1, &id); } Do you know what's wrong with this code ? Here are my OpenGL features : GL_VENDOR: NVIDIA Corporation GL_RENDERER: Quadro FX 3450/4000 SDI/PCI/SSE2 GL_VERSION: 1.5.3 GL_EXTENSIONS: ... GL_ARB_vertex_buffer_object ... (glGenBuffers belongs to the GL_ARB_vertex_buffer_object that I h have) And I have the NVIDIA forceware 72.13 which is not the last one (the last release is the 91.36). Raphael

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based on that code you never initalised the function pointer to point to the correct address, thus calling = calling a null (or even random) address, thus crash town..

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You have to call glewInit(); before calling any OpenGL extensions.

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Thanks for your help. So I initialized the function pointer and added the
glewInit() call but it was still crashing. I eventually added
a glutCreateWindow() call and then it runs normally. The
glewInit() call isn't necessary (here at least).
Here is the code :
//============================================================================
#include <GL/glew.h>
#include <GL/glut.h>
#include <windows.h>
int main(int argc,char **argv) {
GLuint id;
glutCreateWindow("title");
PFNGLGENBUFFERSPROC glGenBuffers = NULL;
PFNGLBINDBUFFERPROC glBindBuffer = NULL;
PFNGLBUFFERDATAPROC glBufferData = NULL;
glGenBuffers = (PFNGLGENBUFFERSPROC)wglGetProcAddress("glGenBuffers");
glBindBuffer = (PFNGLBINDBUFFERPROC)wglGetProcAddress("glBindBuffer");
glBufferData = (PFNGLBUFFERDATAPROC)wglGetProcAddress("glBufferData");
glGenBuffers(1, &id);
glBindBuffer(GL_ARRAY_BUFFER, id);
}
//============================================================================

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I guess it was crashing because u were calling an opengl function before even creating a rendering context etc.

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