# Migrating to 3.0: What to use instead of glfwSleep?

**URL:** <https://discourse.glfw.org/t/migrating-to-3-0-what-to-use-instead-of-glfwsleep/577>\
**Category:** support\
**Created:** [June 13, 2013, 4:03am UTC](https://discourse.glfw.org/t/migrating-to-3-0-what-to-use-instead-of-glfwsleep/577 "2013-06-13T04:03:20Z")\
**Posts on this page:** 1\
**Showing post:** 31

<div class="post-metadata">

**Author:** ![8Observer8](https://avatars.discourse-cdn.com/v4/letter/8/bbe5ce/32.png) [@8Observer8](https://discourse.glfw.org/u/8Observer8)\
**Post date:** [November 11, 2022, 12:15am UTC](https://discourse.glfw.org/t/migrating-to-3-0-what-to-use-instead-of-glfwsleep/577/31 "2022-11-11T00:15:14Z")

</div>

> [@dougbinks](#):
>
> Hopefully that can get you started - if not let me know.

I decided to make a Python version of the above SDL2 C++ example. Please help me write the equivalent code using GLFW3:

```python
maxFPS = 5.0

def main():
    # ...
    running = True
    while running:
        startTicks = SDL_GetTicks()
        # Drawing ...
        # Limit the FPS to the max FPS
        frameTicks = SDL_GetTicks() - startTicks
        if 1000.0 / maxFPS > frameTicks:
            SDL_Delay(int(1000.0 / maxFPS - frameTicks))

```

This is a complete SDL2 example that can be run:

main.py

```python
import ctypes
import sys

from OpenGL.GL import *
from sdl2 import *

maxFPS = 5.0
window: SDL_Window = None

def fatalError(message):
    print(message)
    if window:
        SDL_DestroyWindow(window)
    SDL_Quit()
    exit(-1)

def main():
    if SDL_Init(SDL_INIT_VIDEO) < 0:
        fatalError(SDL_GetError())

    window = SDL_CreateWindow(
        b"OpenGL, SDL2, Python",
        SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
        300, 300,
        SDL_WINDOW_OPENGL)
    if not window:
        fatalError(SDL_GetError())

    context = SDL_GL_CreateContext(window)
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1)
    
    glClearColor(0.65, 0.6, 0.85, 1.0)
    
    event = SDL_Event()
    running = True
    startTicks = 0.0
    frameTicks = 0.0
    while running:
        while SDL_PollEvent(ctypes.byref(event)) != 0:
            if event.type == SDL_QUIT:
                running = False
        startTicks = SDL_GetTicks()

        glClear(GL_COLOR_BUFFER_BIT)
        SDL_GL_SwapWindow(window)
        
        # Limit the FPS to the max FPS
        frameTicks = SDL_GetTicks() - startTicks
        if 1000.0 / maxFPS > frameTicks:
            SDL_Delay(int(1000.0 / maxFPS - frameTicks))
    SDL_GL_DeleteContext(context)
    SDL_DestroyWindow(window)
    SDL_Quit()
    return 0

if __name__ == " __main__":
    sys.exit(main())

```

This is the window using GLFW3:

```python
import ctypes
import sys

from OpenGL.GL import *
import glfw

maxFPS = 5.0
window = None

def fatalError(message):
    print(message)
    glfw.terminate()
    exit(-1)

def main():
    if not glfw.init():
        fatalError("Failed to init GLFW")

    window = glfw.create_window(
        300, 300, "OpenGL, GLFW, Python", None, None)
    if not window:
        fatalError("Failed to create the GLFW window")
    glfw.make_context_current(window)

    glClearColor(0.65, 0.6, 0.85, 1.0)

    while not glfw.window_should_close(window):
        glfw.poll_events()
        glClear(GL_COLOR_BUFFER_BIT)
        glfw.swap_buffers(window)

    glfw.terminate()
    return 0

if __name__ == " __main__":
    sys.exit(main())

```

---

_[View the full topic](https://discourse.glfw.org/t/migrating-to-3-0-what-to-use-instead-of-glfwsleep/577)._