What does glGenBuffers indicate by returning zero? - opengl

Question

My program creates many vertex buffer just after startup as soon as vertex data is loaded over a network, and then occasionally deletes or create vertex buffers during hot loop. It works as expected almost always, but sometimes on some machines buffer creation in hot loop produces zero names.
It doesn't look like an invalid state, because it would fire much earlier. Also, documentation and spec is not clear enough about such type of errors. Does it mean that implementation run out of buffer names?
I also found this thread. Topicstarter says that initializing names before passing them to glGenBuffers fixed his problem. Is it necessary to initialize those values?

Answer 1

Since it seems to work on some machines, glGenBuffer returning 0 could be because of an improperly set up context. Here
davek20 had the same problem with glGenBuffers. He solved it by fixing his incorrect context setup.
As stated on here on GLFW 'Getting started' page, under 'Creating a window and context' they state
"If the required minimum version is not supported on the machine, context (and window) creation fails."
and these machines of yours might have correct drivers but probably doesn't support all or some versions of OpenGL, as the documentation states.
If you are using GLFW_CONTEXT_VERSION_MAJOR and GLFW_CONTEXT_VERSION_MINOR consider changing these. I also recommend checking the context creation for returning NULL (0).
Example from GLFW's documentation page:
GLFWwindow* window;
if (!glfwInit())
return -1;
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
window = glfwCreateWindow(960, 540, "OpenGL", NULL, NULL);
if (!window)
{
glfwTerminate();
return -1;
}