diff --git a/dlls/comcat/comcat_main.c b/dlls/comcat/comcat_main.c
index 7e58d204a2b..33af933f37e 100644
--- a/dlls/comcat/comcat_main.c
+++ b/dlls/comcat/comcat_main.c
@@ -47,7 +47,7 @@ HRESULT WINAPI COMCAT_DllGetClassObject(REFCLSID rclsid, REFIID iid, LPVOID *ppv
 /***********************************************************************
  *		DllCanUnloadNow (COMCAT.@)
  */
-HRESULT WINAPI COMCAT_DllCanUnloadNow()
+HRESULT WINAPI COMCAT_DllCanUnloadNow(void)
 {
     return dll_ref != 0 ? S_FALSE : S_OK;
 }
diff --git a/dlls/d3dxof/main.c b/dlls/d3dxof/main.c
index c1db4dbba08..ad987ea3bd4 100644
--- a/dlls/d3dxof/main.c
+++ b/dlls/d3dxof/main.c
@@ -221,7 +221,7 @@ DWORD WINAPI D3DXOF_DllGetClassObject(REFCLSID rclsid, REFIID riid, LPVOID *ppv)
 /***********************************************************************
  *              DllCanUnloadNow (D3DXOF.@)
  */
-HRESULT WINAPI D3DXOF_DllCanUnloadNow()
+HRESULT WINAPI D3DXOF_DllCanUnloadNow(void)
 {
     return dll_ref != 0 ? S_FALSE : S_OK;
 }
diff --git a/dlls/mpr/mpr.spec b/dlls/mpr/mpr.spec
index 623bf670505..38719185ec4 100644
--- a/dlls/mpr/mpr.spec
+++ b/dlls/mpr/mpr.spec
@@ -23,7 +23,7 @@
 24 stdcall @(ptr) MPR_Free
 25 stdcall @(ptr long) _MPR_25
 
-@ stdcall -private DllCanUnloadNow()
+@ stdcall -private DllCanUnloadNow() MPR_DllCanUnloadNow
 @ stub DllGetClassObject
 @ stdcall MultinetGetConnectionPerformanceA(ptr ptr)
 @ stdcall MultinetGetConnectionPerformanceW(ptr ptr)
diff --git a/dlls/mpr/mpr_main.c b/dlls/mpr/mpr_main.c
index 36feb6818ff..2c8eee76640 100644
--- a/dlls/mpr/mpr_main.c
+++ b/dlls/mpr/mpr_main.c
@@ -75,7 +75,7 @@ BOOL WINAPI _MPR_25( LPBYTE lpMem, INT len )
 /*****************************************************************
  *  DllCanUnloadNow  [MPR.@]
  */
-DWORD WINAPI DllCanUnloadNow(void)
+DWORD WINAPI MPR_DllCanUnloadNow(void)
 {
     FIXME("Stub\n");
     return S_OK;
diff --git a/dlls/oleaut32/oleaut.c b/dlls/oleaut32/oleaut.c
index a8748219912..901c603fa20 100644
--- a/dlls/oleaut32/oleaut.c
+++ b/dlls/oleaut32/oleaut.c
@@ -730,7 +730,7 @@ HRESULT WINAPI OLEAUT32_DllGetClassObject(REFCLSID rclsid, REFIID iid, LPVOID *p
  * RETURNS
  *  Always returns S_FALSE. This dll cannot be unloaded.
  */
-HRESULT WINAPI OLEAUT32_DllCanUnloadNow()
+HRESULT WINAPI OLEAUT32_DllCanUnloadNow(void)
 {
     return S_FALSE;
 }
diff --git a/dlls/olepro32/olepro32stubs.c b/dlls/olepro32/olepro32stubs.c
index 762839bc5d8..d49b0d47911 100644
--- a/dlls/olepro32/olepro32stubs.c
+++ b/dlls/olepro32/olepro32stubs.c
@@ -52,7 +52,7 @@ HRESULT WINAPI OLEPRO32_DllRegisterServer()
 /***********************************************************************
  *		DllCanUnloadNow (OLEPRO32.255)
  */
-HRESULT WINAPI OLEPRO32_DllCanUnloadNow( )
+HRESULT WINAPI OLEPRO32_DllCanUnloadNow(void)
 {
 	FIXME("not implemented (olepro32.dll) \n");
 	return S_OK;