#define WIN32_LEAN_AND_MEAN #include <windows.h> HANDLE mutex = CreateMutex( 0, false, "ThreadLocalMutex"); map<DWORD, void*> g_threadLocal; void* getThreadLocal() { DWORD myId = ::GetCurrentThreadId(); void* pData = 0; WaitForSingleObject( mutex, timeOutInMillis); if (g_threadLocal.contains(myId)) pData = g_threadLocal[myId]; ReleaseMutex( mutex); return pData; } void setThreadLocal(void* pData) { DWORD myId = ::GetCurrentThreadId(); WaitForSingleObject( mutex, timeOutInMillis); g_threadLocal[myId] = pData; ReleaseMutex( mutex); } void example() { void* pData; pData = getThreadLocal(); if (!pData) { pData = AllocateWhatever(); setThreadLocal(pData); } // Use pData here }