diff --git a/dlls/advpack/advpack_private.h b/dlls/advpack/advpack_private.h
index 3f81bba45dd..23babf61dd1 100644
--- a/dlls/advpack/advpack_private.h
+++ b/dlls/advpack/advpack_private.h
@@ -21,10 +21,10 @@
 #ifndef __ADVPACK_PRIVATE_H
 #define __ADVPACK_PRIVATE_H
 
-HRESULT do_ocx_reg(HMODULE hocx, BOOL do_reg);
-LPWSTR get_parameter(LPWSTR *params, WCHAR separator);
-void set_ldids(HINF hInf, LPCWSTR pszInstallSection, LPCWSTR pszWorkingDir);
+HRESULT do_ocx_reg(HMODULE hocx, BOOL do_reg) DECLSPEC_HIDDEN;
+LPWSTR get_parameter(LPWSTR *params, WCHAR separator) DECLSPEC_HIDDEN;
+void set_ldids(HINF hInf, LPCWSTR pszInstallSection, LPCWSTR pszWorkingDir) DECLSPEC_HIDDEN;
 
-HRESULT launch_exe(LPCWSTR cmd, LPCWSTR dir, HANDLE *phEXE);
+HRESULT launch_exe(LPCWSTR cmd, LPCWSTR dir, HANDLE *phEXE) DECLSPEC_HIDDEN;
 
 #endif /* __ADVPACK_PRIVATE_H */