diff --git a/src/win32_init.c b/src/win32_init.c
index a7a6be6..22c1ba7 100644
--- a/src/win32_init.c
+++ b/src/win32_init.c
@@ -39,6 +39,10 @@
 
 #if defined(_GLFW_USE_HYBRID_HPG) || defined(_GLFW_USE_OPTIMUS_HPG)
 
+#if defined(_GLFW_BUILD_DLL)
+ #warning "These symbols must be exported by the executable and have no effect in a DLL"
+#endif
+
 // Executables (but not DLLs) exporting this symbol with this value will be
 // automatically directed to the high-performance GPU on Nvidia Optimus systems
 // with up-to-date drivers