diff --git a/dlls/difxapi/difxapi.spec b/dlls/difxapi/difxapi.spec
index 33a805b7958..3e2f8595e12 100644
--- a/dlls/difxapi/difxapi.spec
+++ b/dlls/difxapi/difxapi.spec
@@ -8,3 +8,5 @@
 @ stdcall DriverPackagePreinstallW(wstr long)
 @ stdcall DriverPackageUninstallA(str long ptr ptr)
 @ stdcall DriverPackageUninstallW(wstr long ptr ptr)
+@ stdcall SetDifxLogCallbackA(ptr ptr)
+@ stdcall SetDifxLogCallbackW(ptr ptr)
diff --git a/dlls/difxapi/main.c b/dlls/difxapi/main.c
index 8a2679cd4ec..7b7b1d6d949 100644
--- a/dlls/difxapi/main.c
+++ b/dlls/difxapi/main.c
@@ -86,3 +86,13 @@ VOID WINAPI DIFXAPISetLogCallbackW(DIFXAPILOGCALLBACK_W cb, VOID *ctx)
 {
     FIXME("(%p, %p) stub\n", cb, ctx);
 }
+
+VOID WINAPI SetDifxLogCallbackA(DIFXLOGCALLBACK_A cb, VOID *ctx)
+{
+    FIXME("(%p, %p) stub\n", cb, ctx);
+}
+
+VOID WINAPI SetDifxLogCallbackW(DIFXLOGCALLBACK_W cb, VOID *ctx)
+{
+    FIXME("(%p, %p) stub\n", cb, ctx);
+}
diff --git a/include/difxapi.h b/include/difxapi.h
index f5149b8b0b9..21d43c90de6 100644
--- a/include/difxapi.h
+++ b/include/difxapi.h
@@ -51,6 +51,8 @@ typedef enum _DIFXAPI_LOG
 
 typedef VOID (CALLBACK *DIFXAPILOGCALLBACK_A)(DIFXAPI_LOG,DWORD,PCSTR,PVOID);
 typedef VOID (CALLBACK *DIFXAPILOGCALLBACK_W)(DIFXAPI_LOG,DWORD,PCWSTR,PVOID);
+typedef VOID (CALLBACK *DIFXLOGCALLBACK_A)(DIFXAPI_LOG,DWORD,PCSTR,PVOID);
+typedef VOID (CALLBACK *DIFXLOGCALLBACK_W)(DIFXAPI_LOG,DWORD,PCWSTR,PVOID);
 
 VOID  WINAPI DIFXAPISetLogCallbackA(DIFXAPILOGCALLBACK_A,VOID*);
 VOID  WINAPI DIFXAPISetLogCallbackW(DIFXAPILOGCALLBACK_W,VOID*);
@@ -62,6 +64,8 @@ DWORD WINAPI DriverPackagePreinstallA(PCSTR,DWORD);
 DWORD WINAPI DriverPackagePreinstallW(PCWSTR,DWORD);
 DWORD WINAPI DriverPackageUninstallA(PCSTR,DWORD,PCINSTALLERINFO_A,BOOL*);
 DWORD WINAPI DriverPackageUninstallW(PCWSTR,DWORD,PCINSTALLERINFO_W,BOOL*);
+VOID  WINAPI SetDifxLogCallbackA(DIFXLOGCALLBACK_A,VOID*);
+VOID  WINAPI SetDifxLogCallbackW(DIFXLOGCALLBACK_W,VOID*);
 
 #ifdef __cplusplus
 }