1 背景
通过串口终端启动arm开发板（linux系统）的Qt应用程序，提示：
- [root@FORLINX6410]# /opt/qt-4.7.1/demos/textedit/textedit
- s3c-nand: 1 bit(s) error detected, corrected successfully
- QWSSocket::connectToLocalFile could not connect:: No such file or directory
- QWSSocket::connectToLocalFile could not connect:: No such file or directory
- QWSSocket::connectToLocalFile could not connect:: No such file or directory
- QWSSocket::connectToLocalFile could not connect:: No such file or directory
- QWSSocket::connectToLocalFile could not connect:: No such file or directory
- QWSSocket::connectToLocalFile could not connect:: No such file or directory
- No Qt for Embedded Linux server appears to be running.
- If you want to run this program as a server,
- add the "-qws" command-line option.
根据提示，加上-qws参数后，可以正确启动。
2 WQS
根据参考资料[2]的说明，QWS的全称是Qt windows system，是QT自行开发的窗口系统，体系结构类似X Windows，是一个C/S结构，由QWS Server在物理设备上显示，由QWS Client实现界面，两者通过socket进行彼此的通讯。在很多嵌入式系统里，QT程序基本上都是用QWS来实现，这样保证程序的可移植性。
3 QPA
参考资料[5]P18指出，Qt5中已经抛弃了QWS框架，改为使用QPA框架。
参考资料
[2]QT中QWS的含义
[3]关于QWSServer
[5]《Qt5编程入门》