for .. C
(HANDLE)_beginthreadex(NULL, 0, ClientConn, (void*)clntSock, 0, (unsigned *)&dwThreadID);
for .. C++
(HANDLE)_beginthreadex(NULL, 0, (unsigned int(__stdcall*)(void*))ClientConn, (void*)clntSock, 0, (unsigned *)&dwThreadID);
CreateThread 라는 함수도 있음..