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Qt broadcastreceiver 在 Linux 上不能与 sender 一起使用。发件人是用c写的。

我已经在 Windows 上用 Qt 广播发送器测试了 Qt 广播接收器，这没问题，而且 Qt 广播发送器在 C 中的 linux 接收器上也能正常工作。

在 Windows 上从 linux 接收数据时可能出现什么问题。

这是相同的代码。

发件人（Qt/windows）：main.cpp

#include <QApplication>
#include "receiver.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Receiver receiver;
    receiver.show();
    return app.exec();
}

接收器.h

#ifndef RECEIVER_H
#define RECEIVER_H

#include <QtGui>
#include <QtNetwork/QUdpSocket>
#include <QWidget>

class Receiver : public QWidget
{
    Q_OBJECT

public:
    Receiver(QWidget *parent = 0);

private slots:
    void processPendingDatagrams();

private:
    QLabel *statusLabel;
    QPushButton *quitButton;
    QUdpSocket *udpSocket;
};

#endif

接收器.cpp

#include <QtGui>
#include <QtNetwork>

#include "receiver.h"

#define PORT 45454

Receiver::Receiver(QWidget *parent): QWidget(parent)
{
    statusLabel = new QLabel(tr("Listening for broadcasted messages"));
    statusLabel->setWordWrap(true);

    quitButton = new QPushButton(tr("&Quit"));

    udpSocket = new QUdpSocket(this);
    bool b = udpSocket->bind(QHostAddress::Any,PORT, QUdpSocket::ShareAddress);

    connect(udpSocket, SIGNAL(readyRead()), this, SLOT(processPendingDatagrams()));
    connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));

    QHBoxLayout *buttonLayout = new QHBoxLayout;
    buttonLayout->addStretch(1);
    buttonLayout->addWidget(quitButton);
    buttonLayout->addStretch(1);

    QVBoxLayout *mainLayout = new QVBoxLayout;
    mainLayout->addWidget(statusLabel);
    mainLayout->addLayout(buttonLayout);
    setLayout(mainLayout);

    setWindowTitle(tr("Broadcast Receiver"));
}

void Receiver::processPendingDatagrams()
{
    while (udpSocket->hasPendingDatagrams())
    {
        QByteArray datagram;
        datagram.resize(udpSocket->pendingDatagramSize());
        udpSocket->readDatagram(datagram.data(), datagram.size());
        statusLabel->setText(statusLabel->text() + tr("Received datagram: \"%1\"").arg(datagram.data()));
    }
}

广播接收器.pro

HEADERS       = receiver.h
SOURCES       = receiver.cpp \
                main.cpp
QT           += network

# install
target.path = $$[QT_INSTALL_EXAMPLES]/network/broadcastreceiver
sources.files = $$SOURCES $$HEADERS $$RESOURCES $$FORMS broadcastreceiver.pro
sources.path = $$[QT_INSTALL_EXAMPLES]/network/broadcastreceiver
INSTALLS += target sources

symbian: {
    TARGET.CAPABILITY = NetworkServices
    include($$PWD/../../symbianpkgrules.pri)
}
maemo5: include($$PWD/../../maemo5pkgrules.pri)
contains(MEEGO_EDITION,harmattan): include($$PWD/../../harmattanpkgrules.pri)

发件人.c (C/Linux)

#include <stdio.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>

#define BUFLEN 512
#define NPACK 10
#define PORT 45454

#define SRV_IP "xxx.xxx.xxx.xxx"

void diep(char *s)
{
    perror(s);
    exit(1);
}


int main(void)
{
    struct sockaddr_in si_other;
    int s, i, slen=sizeof(si_other);
    char buf[BUFLEN];

    if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP))==-1)
    {
        diep("socket");
        printf("\n\tSocket error\n");
    }

    memset((char *) &si_other, 0, sizeof(si_other));
    si_other.sin_family = AF_INET;
    si_other.sin_port = htons(PORT);
    if (inet_aton(SRV_IP, &si_other.sin_addr)==0)
    {
         fprintf(stderr, "inet_aton() failed\n");
        printf("\n\tInet_aton error\n");
        exit(1);
    }

    for (i=0;; i++)
    {
        printf("Sending packet %d\n", i);
        sprintf(buf, "This is packet %d\n", i);
        if (sendto(s, buf, BUFLEN, 0, &si_other, slen)==-1)
     {
            diep("sendto()");
         printf("\n\tSendto error\n");
     }

    printf("Data written on (IP = %s and port : %d\n\n",inet_ntoa(si_other.sin_addr),ntohs(si_other.sin_port));
    sleep(1);
    }

    close(s);
    return 0;
}

问候， Gurmeet

4

1 回答 1

1

我已经尝试了您的代码，几乎一切正常。唯一的问题是，到达的包裹没有在您的视图中正确显示。第一个包裹到达后，上面写着：

Listening for broadcasted messagesReceived datagram: "This is packet

然后它停止，因为数据包的内容是终止 QString 的 0 字节。这也意味着不再显示所有后续消息。

我不知道这是否解决了您的问题，也许根本没有数据到达。我使用的是 Linux，我无法向您保证任何适用于 Windows 的内容（尽管 Qt 在 Windows 上的运行效果应该与在 Linux 上一样好），但我可以向您保证您的代码在 Linux 上运行。

于 2012-08-05T13:42:18.990 回答