在linux中，我想用QT写个程序来向本地路由器的DHCP服务器申请IP地址，并获取网关、子网掩码和DNS,写一个C++的例子

好的，以下是一个简单的C++例子，使用QT库向本地路由器的DHCP服务器申请IP地址，并获取网关、子网掩码和DNS：

#include <QCoreApplication>
#include <QNetworkInterface>
#include <QNetworkAddressEntry>
#include <QProcess>

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

    // 获取本地网络接口列表
    QList<QNetworkInterface> interfaces = QNetworkInterface::allInterfaces();

    // 遍历接口列表，找到第一个支持DHCP的接口
    QNetworkInterface dhcpInterface;
    foreach (QNetworkInterface iface, interfaces) {
        if (iface.flags().testFlag(QNetworkInterface::IsUp) &&
            iface.flags().testFlag(QNetworkInterface::IsRunning) &&
            !iface.flags().testFlag(QNetworkInterface::IsLoopBack)) {
            QList<QNetworkAddressEntry> entries = iface.addressEntries();
            foreach (QNetworkAddressEntry entry, entries) {
                if (entry.dhcp()) {
                    dhcpInterface = iface;
                    break;
                }
            }
        }
    }

    // 如果找到支持DHCP的接口，执行dhclient命令来获取IP地址、网关、子网掩码和DNS
    if (!dhcpInterface.isNull()) {
        QString interfaceName = dhcpInterface.name();
        QProcess process;
        process.start("dhclient " + interfaceName);
        if (process.waitForFinished()) {
            QString output = process.readAllStandardOutput();
            QStringList lines = output.split("\n");
            QString ipAddress, gateway, netmask, dns;
            foreach (QString line, lines) {
                if (line.contains("bound to")) {
                    ipAddress = line.section(" ", 2).trimmed();
                } else if (line.contains("routers")) {
                    gateway = line.section(" ", 2).trimmed();
                } else if (line.contains("subnet mask")) {
                    netmask = line.section(" ", 2).trimmed();
                } else if (line.contains("domain-name-servers")) {
                    dns = line.section(" ", 2).trimmed();
                }
            }

            // 输出获取到的IP地址、网关、子网掩码和DNS
            qDebug() << "IP address: " << ipAddress;
            qDebug() << "Gateway: " << gateway;
            qDebug() << "Netmask: " << netmask;
            qDebug() << "DNS: " << dns;
        }
    }

    return a.exec();
}

请注意，这个例子只能在Linux系统上运行，并且需要root权限才能执行dhclient命令。