live555很多这种函数返回 unsigned
unsigned RTSPServer::registerStream(ServerMediaSession* serverMediaSession,
char const* remoteClientNameOrAddress, portNumBits remoteClientPortNum,
responseHandlerForREGISTER* responseHandler,
char const* username, char const* password,
Boolean receiveOurStreamViaTCP, char const* proxyURLSuffix)
unsigned其实是unsigned int,表示无符号整形,可以省略int,跟unsigned int等价