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//! [0]

class MyDaemon : public QObject

{

    Q_OBJECT

  public:

    MyDaemon(QObject *parent = 0, const char *name = 0);

    ~MyDaemon();

    // Unix signal handlers.

    static void hupSignalHandler(int unused);

    static void termSignalHandler(int unused);

  public slots:

    // Qt signal handlers.

    void handleSigHup();

    void handleSigTerm();

  private:

    static int sighupFd[2];

    static int sigtermFd[2];

    QSocketNotifier *snHup;

    QSocketNotifier *snTerm;

};

//! [0]

//! [1]

MyDaemon::MyDaemon(QObject *parent, const char *name)

    	 : QObject(parent,name)

{

    if (::socketpair(AF_UNIX, SOCK_STREAM, 0, sighupFd))

       qFatal("Couldn't create HUP socketpair");

    if (::socketpair(AF_UNIX, SOCK_STREAM, 0, sigtermFd))

       qFatal("Couldn't create TERM socketpair");

    snHup = new QSocketNotifier(sighupFd[1], QSocketNotifier::Read, this);

    connect(snHup, SIGNAL(activated(int)), this, SLOT(handleSigHup()));

    snTerm = new QSocketNotifier(sigtermFd[1], QSocketNotifier::Read, this);

    connect(snTerm, SIGNAL(activated(int)), this, SLOT(handleSigTerm()));

    ...

}

//! [1]

//! [2]

static int setup_unix_signal_handlers()

{

    struct sigaction hup, term;

    hup.sa_handler = MyDaemon::hupSignalHandler;

    sigemptyset(&hup.sa_mask);

    hup.sa_flags = 0;

    hup.sa_flags |= SA_RESTART;

    if (sigaction(SIGHUP, &hup, 0) > 0)

       return 1;

    term.sa_handler = MyDaemon::termSignalHandler;

    sigemptyset(&term.sa_mask);

    term.sa_flags |= SA_RESTART;

    if (sigaction(SIGTERM, &term, 0) > 0)

       return 2;

    return 0;

}

//! [2]

//! [3]

void MyDaemon::hupSignalHandler(int)

{

    char a = 1;

    ::write(sighupFd[0], &a, sizeof(a));

}

void MyDaemon::termSignalHandler(int)

{

    char a = 1;

    ::write(sigtermFd[0], &a, sizeof(a));

}

//! [3]

//! [4]

void MyDaemon::handleSigTerm()

{

    snTerm->setEnabled(false);

    char tmp;

    ::read(sigtermFd[1], &tmp, sizeof(tmp));

    // do Qt stuff

    snTerm->setEnabled(true);

}

void MyDaemon::handleSigHup()

{

    snHup->setEnabled(false);

    char tmp;

    ::read(sighupFd[1], &tmp, sizeof(tmp));

    // do Qt stuff

    snHup->setEnabled(true);

}

//! [4]