QT快速使用ntohs，需要注意3点：
1. ntohs只是转换相邻的2个字节
2. 引入头文件#include <windows.h>
3. 需要加上win32{LIBS+=-lws2_32}
下面是一个简单的小例子：
#include <QtGui/QApplication> #include <QDebug> #include <windows.h> int main(int argc, char *argv[]) { QApplication a(argc, argv); qDebug("unsigned int: %d", sizeof(unsigned int)); qDebug("unsigned int: %d", sizeof(unsigned short)); unsigned int uia = 4; unsigned short usa = 4; unsigned int uib = 1024; unsigned short usb = 1024; qDebug("00000000 00000000 00000100 00000000(1024)-->(4)00000000 00000000 00000000 00000100: %d",ntohs(uib)); qDebug("00000000 00000000 00000000 00000100(4)-->(1024)00000000 00000000 00000100 00000000: %d",ntohs(uia)); qDebug("00000100 00000000(1024)-->(4)00000000 00000100: %d",ntohs(usb)); qDebug("00000000 00000100(4)-->(1024)00000100 00000000: %d",ntohs(usa)); return a.exec(); }
可以看出,尽管int是32位的，但实际上只是2个字节之间的交换。
原文：http://www.cnblogs.com/UnMovedMover/p/3540393.html