# Resize callback stall

**URL:** <https://discourse.glfw.org/t/resize-callback-stall/117>\
**Category:** support\
**Created:** [January 9, 2015, 1:07am UTC](https://discourse.glfw.org/t/resize-callback-stall/117 "2015-01-09T01:07:46Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![system](https://canada1.discourse-cdn.com/flex035/uploads/glfw/original/1X/b8cdefe6b61b8d5aee6c43b2c56e9cf5eabecfe4.svg) [@system](https://discourse.glfw.org/u/system)\
**Post date:** [January 9, 2015, 1:07am UTC](https://discourse.glfw.org/t/resize-callback-stall/117/1 "2015-01-09T01:07:46Z")

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**[tuomlarsen](https://sourceforge.net/u/tuomlarsen/)** wrote on [Friday, January 09, 2015](https://sourceforge.net/p/glfw/discussion/247562/thread/c5163cd5/#ed0f):

Hi!

I’m very new to this OpenGL thing and to GLFW as well.

I’m trying to display a simple triangle and it works! However, the problem is that when I resize the window by dragging the lower-right corner nothing happens (not even the redrawing, i.e. various artifacts show up) during the dragging, until I release the mouse button. I’m on MacOS X and using GLFW 3.0.4.

I set up the “glfwSetWindowSizeCallback()” handler and it gets called, like this:

static void window\_size\_callback(GLFWwindow \*window, int width, int height) {  
glViewport(0, 0, width, height);  
printf(“was called\n”);  
}

I read that it is caused by the OS event loop and I verified the supplied examples, all of which exhibit the said behavior.

Please, how do I make it “live” resize? Are there any examples of this?

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**Author:** ![yairchu](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.glfw.org/yairchu/32/766_2.png) [@yairchu](https://discourse.glfw.org/u/yairchu)\
**Post date:** [May 7, 2023, 8:27am UTC](https://discourse.glfw.org/t/resize-callback-stall/117/2 "2023-05-07T08:27:06Z")

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I made a patch to GLFW to solve this issue, see here: [Followup: MacOS event processing blocks during window resizing using glfwPollEvents · Issue #2008 · glfw/glfw · GitHub](https://github.com/glfw/glfw/issues/2008#issuecomment-1534856957)