最近在开发im服务器，需要大并发链接。QT默认的是使用select模型的，这种轮询方式非常慢。在高并发连接,我们需要epoll才能发挥linux服务器的性能.而且使用简单,整个服务端代码架构无需修改,设置QT的分发事件就可以使用了,只要在main里面添加 :

int main(int argc, char *argv[])
{


  #ifdef Q_OS_LINUX
    QCoreApplication::setEventDispatcher(new EventDispatcherLibEvent);
   // qInstallMessageHandler(customMessageHandler);
  #endif


  QCoreApplication a(argc, argv);


  auto *ser=new ConfigServer;
  ser->startServer();


  return a.exec();
}

在.pro文件添加

linux{
    LIBS += -levent_core


    SOURCES += ../common/eventdispatcher_libevent/eventdispatcher_libevent.cpp \
    ../common/eventdispatcher_libevent/eventdispatcher_libevent_config.cpp \
    ../common/eventdispatcher_libevent/eventdispatcher_libevent_p.cpp \
    ../common/eventdispatcher_libevent/socknot_p.cpp \
    ../common/eventdispatcher_libevent/tco_eventfd.cpp \
    ../common/eventdispatcher_libevent/tco_pipe.cpp \
    ../common/eventdispatcher_libevent/tco.cpp \
    ../common/eventdispatcher_libevent/timers_p.cpp


    HEADERS += ../common/eventdispatcher_libevent/common.h \
    ../common/eventdispatcher_libevent/eventdispatcher_libevent.h \
    ../common/eventdispatcher_libevent/eventdispatcher_libevent_config.h \
    ../common/eventdispatcher_libevent/eventdispatcher_libevent_config_p.h \
    ../common/eventdispatcher_libevent/eventdispatcher_libevent_p.h \
    ../common/eventdispatcher_libevent/libevent2-emul.h \
    ../common/eventdispatcher_libevent/qt4compat.h \
    ../common/eventdispatcher_libevent/tco.h \
    ../common/eventdispatcher_libevent/wsainit.h


    }

可以直接跨平台了使用了

附上qt libevent源码下载地址：http://download.csdn.net/detail/rushroom/7968573