diff --git a/patches/dsdmo-new-dll/0006-dsdmo-Add-IDirectSoundFXFlanger-support.patch b/patches/dsdmo-new-dll/0006-dsdmo-Add-IDirectSoundFXFlanger-support.patch
index c57545d8..54c0ee4d 100644
--- a/patches/dsdmo-new-dll/0006-dsdmo-Add-IDirectSoundFXFlanger-support.patch
+++ b/patches/dsdmo-new-dll/0006-dsdmo-Add-IDirectSoundFXFlanger-support.patch
@@ -306,13 +306,13 @@ index 0000000000..6fbc836dcd
 +    return IDirectSoundFXFlanger_QueryInterface(&This->IDirectSoundFXFlanger_iface, riid, obj);
 +}
 +
-+static ULONG flanger_mediainplace_AddRef(IMediaObjectInPlace *iface)
++static ULONG WINAPI flanger_mediainplace_AddRef(IMediaObjectInPlace *iface)
 +{
 +    struct dmo_flangerfx *This = impl_from_IMediaObjectInPlace(iface);
 +    return IDirectSoundFXFlanger_AddRef(&This->IDirectSoundFXFlanger_iface);
 +}
 +
-+static ULONG flanger_mediainplace_Release(IMediaObjectInPlace *iface)
++static ULONG WINAPI flanger_mediainplace_Release(IMediaObjectInPlace *iface)
 +{
 +    struct dmo_flangerfx *This = impl_from_IMediaObjectInPlace(iface);
 +    return IDirectSoundFXFlanger_Release(&This->IDirectSoundFXFlanger_iface);