diff --git a/include/winbase.h b/include/winbase.h
index ad51af3c263..4e210498309 100644
--- a/include/winbase.h
+++ b/include/winbase.h
@@ -1951,6 +1951,8 @@ WINADVAPI  BOOL        WINAPI InitializeSecurityDescriptor(PSECURITY_DESCRIPTOR,
 WINADVAPI  BOOL        WINAPI InitializeSid(PSID,PSID_IDENTIFIER_AUTHORITY,BYTE);
 WINBASEAPI VOID        WINAPI InitializeSListHead(PSLIST_HEADER);
 WINBASEAPI VOID        WINAPI InitializeSRWLock(PSRWLOCK);
+WINBASEAPI BOOL        WINAPI InitOnceBeginInitialize(PINIT_ONCE, DWORD, PBOOL, PVOID*);
+WINBASEAPI BOOL        WINAPI InitOnceComplete(PINIT_ONCE, DWORD, PVOID);
 WINBASEAPI BOOL        WINAPI InitOnceExecuteOnce(PINIT_ONCE,PINIT_ONCE_FN,PVOID,PVOID*);
 WINBASEAPI VOID        WINAPI InitOnceInitialize(PINIT_ONCE);
 WINBASEAPI PSLIST_ENTRY WINAPI InterlockedFlushSList(PSLIST_HEADER);
diff --git a/include/winnt.h b/include/winnt.h
index 6911f1c40a0..171141e25e6 100644
--- a/include/winnt.h
+++ b/include/winnt.h
@@ -5163,6 +5163,8 @@ typedef DWORD WINAPI RTL_RUN_ONCE_INIT_FN(PRTL_RUN_ONCE, PVOID, PVOID*);
 typedef RTL_RUN_ONCE_INIT_FN *PRTL_RUN_ONCE_INIT_FN;
 NTSYSAPI VOID WINAPI RtlRunOnceInitialize(PRTL_RUN_ONCE);
 NTSYSAPI DWORD WINAPI RtlRunOnceExecuteOnce(PRTL_RUN_ONCE,PRTL_RUN_ONCE_INIT_FN,PVOID,PVOID*);
+NTSYSAPI DWORD WINAPI RtlRunOnceBeginInitialize(PRTL_RUN_ONCE, DWORD, PBOOL, PVOID*);
+NTSYSAPI DWORD WINAPI RtlRunOnceComplete(PRTL_RUN_ONCE, DWORD, PVOID);
 
 #include <pshpack8.h>
 typedef struct _IO_COUNTERS {