The window whose callback to set.
The new callback, or null to remove the currently set callback.
The previously set callback, or null if no callback was set or the library had not been initialized.
@callback_signature
void function_name(GLFWwindow* window, int entered)
For more information about the callback parameters, see the function pointer type.
Errors: Possible errors include @ref GLFW_NOT_INITIALIZED.
This function must only be called from the main thread.
@sa @ref cursor_enter
Added in version 3.0.
Ingroup: input
Sets the cursor enter/leave callback.
This function sets the cursor boundary crossing callback of the specified window, which is called when the cursor enters or leaves the content area of the window.