diff --git a/src/cocoa_init.m b/src/cocoa_init.m
index 15dc4ec4..f1e0bad4 100644
--- a/src/cocoa_init.m
+++ b/src/cocoa_init.m
@@ -555,6 +555,7 @@ GLFWbool _glfwConnectCocoa(int platformID, _GLFWplatform* platform)
         .setWindowFloating = _glfwSetWindowFloatingCocoa,
         .setWindowOpacity = _glfwSetWindowOpacityCocoa,
         .setWindowMousePassthrough = _glfwSetWindowMousePassthroughCocoa,
+        .getWindowIsFullscreen = _glfwGetWindowIsFullscreenNull,
         .pollEvents = _glfwPollEventsCocoa,
         .waitEvents = _glfwWaitEventsCocoa,
         .waitEventsTimeout = _glfwWaitEventsTimeoutCocoa,
diff --git a/src/win32_init.c b/src/win32_init.c
index 77ab56ba..a30ebb18 100644
--- a/src/win32_init.c
+++ b/src/win32_init.c
@@ -664,6 +664,7 @@ GLFWbool _glfwConnectWin32(int platformID, _GLFWplatform* platform)
         .setWindowFloating = _glfwSetWindowFloatingWin32,
         .setWindowOpacity = _glfwSetWindowOpacityWin32,
         .setWindowMousePassthrough = _glfwSetWindowMousePassthroughWin32,
+        .getWindowIsFullscreen = _glfwGetWindowIsFullscreenNull,
         .pollEvents = _glfwPollEventsWin32,
         .waitEvents = _glfwWaitEventsWin32,
         .waitEventsTimeout = _glfwWaitEventsTimeoutWin32,
diff --git a/src/wl_init.c b/src/wl_init.c
index ef9e4503..859cf29f 100644
--- a/src/wl_init.c
+++ b/src/wl_init.c
@@ -506,6 +506,7 @@ GLFWbool _glfwConnectWayland(int platformID, _GLFWplatform* platform)
         .setWindowFloating = _glfwSetWindowFloatingWayland,
         .setWindowOpacity = _glfwSetWindowOpacityWayland,
         .setWindowMousePassthrough = _glfwSetWindowMousePassthroughWayland,
+        .getWindowIsFullscreen = _glfwGetWindowIsFullscreenNull,
         .pollEvents = _glfwPollEventsWayland,
         .waitEvents = _glfwWaitEventsWayland,
         .waitEventsTimeout = _glfwWaitEventsTimeoutWayland,