QByteArray ba;unsignedint a =0x12345678;unsignedshort b =0x1234;unsignedchar c =0x12;
ba.append(QByteArray((constchar*)&b,sizeof(unsignedshort)));
ba.append(QByteArray((constchar*)&c,sizeof(unsignedchar)));
ba.append(QByteArray((constchar*)&a,sizeof(unsignedint)));