diff --git a/samples/pong/build.sh b/samples/pong/build.sh
index 028d57a..a1d1233 100755
--- a/samples/pong/build.sh
+++ b/samples/pong/build.sh
@@ -4,7 +4,7 @@ wasmFlags="--target=wasm32 \
        --no-standard-libraries \
        -fno-builtin \
        -Wl,--no-entry \
-       -Wl,--export-all \
+       -Wl,--export-dynamic \
        -Wl,--allow-undefined \
        -g \
        -D__ORCA__ \
diff --git a/samples/pong/src/main.c b/samples/pong/src/main.c
index ac9f4c7..9d35a82 100644
--- a/samples/pong/src/main.c
+++ b/samples/pong/src/main.c
@@ -36,7 +36,7 @@ mg_image image;
 
 mg_surface mg_surface_main(void);
 
-void OnInit(void)
+ORCA_EXPORT void OnInit(void)
 {
 	//TODO create surface for main window
 	surface = mg_surface_main();
@@ -70,19 +70,19 @@ void OnInit(void)
 	mem_arena_clear(mem_scratch());
 }
 
-void OnFrameResize(u32 width, u32 height)
+ORCA_EXPORT void OnFrameResize(u32 width, u32 height)
 {
 	log_info("frame resize %u, %u", width, height);
 	frameSize.x = width;
 	frameSize.y = height;
 }
 
-void OnMouseDown(int button)
+ORCA_EXPORT void OnMouseDown(int button)
 {
 	log_info("mouse down!");
 }
 
-void OnKeyDown(int key)
+ORCA_EXPORT void OnKeyDown(int key)
 {
 	if(key == KEY_SPACE)
 	{
@@ -106,7 +106,7 @@ void OnKeyDown(int key)
 	}
 }
 
-void OnKeyUp(int key)
+ORCA_EXPORT void OnKeyUp(int key)
 {
 	if(key == KEY_ENTER || key == KEY_SPACE)
 	{
@@ -124,7 +124,7 @@ void OnKeyUp(int key)
 	}
 }
 
-void OnFrameRefresh(void)
+ORCA_EXPORT void OnFrameRefresh(void)
 {
 	f32 aspect = frameSize.x/frameSize.y;
 
diff --git a/sdk/orca.h b/sdk/orca.h
index 0aacce1..9f7e8e5 100644
--- a/sdk/orca.h
+++ b/sdk/orca.h
@@ -13,8 +13,15 @@
 #include"util/memory.h"
 #include"util/strings.h"
 #include"util/utf8.h"
+#include"platform/platform.h"
 #include"platform/platform_log.h"
 #include"platform/platform_assert.h"
 #include"platform/platform_io.h"
 
+#if COMPILER_CLANG
+	#define ORCA_EXPORT __attribute__((visibility("default")))
+#else
+	#error "Orca apps can only be compiled with clang for now"
+#endif
+
 #endif //__ORCA_H_