diff --git a/include/bx/os.h b/include/bx/os.h
index 9abcbc8..6f9257e 100644
--- a/include/bx/os.h
+++ b/include/bx/os.h
@@ -80,6 +80,7 @@ namespace bx
 #if BX_PLATFORM_WINDOWS
 		return (void*)::LoadLibraryA(_filePath);
 #elif BX_PLATFORM_NACL
+		BX_UNUSED(_filePath);
 		return NULL;
 #else
 		return ::dlopen(_filePath, RTLD_LOCAL|RTLD_LAZY);
@@ -91,6 +92,7 @@ namespace bx
 #if BX_PLATFORM_WINDOWS
 		::FreeLibrary( (HMODULE)_handle);
 #elif BX_PLATFORM_NACL
+		BX_UNUSED(_handle);
 #else
 		::dlclose(_handle);
 #endif // BX_PLATFORM_
@@ -101,6 +103,7 @@ namespace bx
 #if BX_PLATFORM_WINDOWS
 		return (void*)::GetProcAddress( (HMODULE)_handle, _symbol);
 #elif BX_PLATFORM_NACL
+		BX_UNUSED(_handle, _symbol);
 		return NULL;
 #else
 		return ::dlsym(_handle, _symbol);
diff --git a/include/bx/sem.h b/include/bx/sem.h
index 0e6f516..5141a13 100644
--- a/include/bx/sem.h
+++ b/include/bx/sem.h
@@ -152,7 +152,7 @@ namespace bx
 		bool wait(int32_t _msecs = -1)
 		{
 #		if BX_PLATFORM_NACL || BX_PLATFORM_OSX
-			BX_CHECK(-1 == _msecs, "NaCl and OSX don't support sem_timedwait at this moment.");
+			BX_CHECK(-1 == _msecs, "NaCl and OSX don't support sem_timedwait at this moment."); BX_UNUSED(_msecs);
 			return 0 == sem_wait(&m_handle);
 #		else
 			if (0 > _msecs)