RtlpGetStackLimitsEx

BOOL __fastcall RtlpGetStackLimitsEx(UINT64 a1, CHAR **rdx0, UINT64 *a3){
  BOOL result; 
  int a2; 
  result = KeQueryCurrentStackInformationEx(a1, &a2, rdx0, a3);
  if( !result )
    __fastfail(4u);
  return result;
}

Referenced by:

RtlDispatchException
RtlUnwindEx