Question

Qt broadcastreceiver无法在Linux上使用发件人。发件人写在c。

我已经在Windows上使用Qt broadcastsender测试了Qt broadcastreceiver，这是正常的，并且Qt broadcastsender也可以在C语言的linux接收器中正常工作。

在Windows上从linux接收数据时可能出现的问题。

这是相同的代码。

发件人（Qt / windows）： main.cpp中

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

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

receiver.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

receiver.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()));
    }
}

broadcastreceiver.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)

sender.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;
}

此致 Gurmeet

Answer 1

我已经尝试过你的代码，几乎所有东西都运行正常。唯一的问题是，到达的包在您的视图中无法正确显示。第一个包裹到货后，它说：

Listening for broadcasted messagesReceived datagram: "This is packet

然后停止，因为数据包的内容是0字节，终止QString。这也意味着不再显示以下所有消息。

我不知道这是否能解决您的问题，也许根本没有数据到来。我正在使用Linux，我无法向你保证Windows的任何东西（虽然Qt在Windows上也可以在Linux上运行）但我可以向你保证你的代码在Linux上工作。

Linux上的C中的UDP发送方和Windows上的Qt中的接收方不起作用？

1 个答案: