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     2 **

     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

     4 ** All rights reserved.

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     7 ** This file is part of the documentation of the Qt Toolkit.

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     9 ** $QT_BEGIN_LICENSE:LGPL$

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    16 ** GNU Lesser General Public License Usage

    17 ** Alternatively, this file may be used under the terms of the GNU Lesser

    18 ** General Public License version 2.1 as published by the Free Software

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    38 ** $QT_END_LICENSE$

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    40 ****************************************************************************/

    41 

    42 //! [0]

    43 class MyDaemon : public QObject

    44 {

    45     Q_OBJECT

    46 

    47   public:

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

    49     ~MyDaemon();

    50 

    51     // Unix signal handlers.

    52     static void hupSignalHandler(int unused);

    53     static void termSignalHandler(int unused);

    54 

    55   public slots:

    56     // Qt signal handlers.

    57     void handleSigHup();

    58     void handleSigTerm();

    59 

    60   private:

    61     static int sighupFd[2];

    62     static int sigtermFd[2];

    63 

    64     QSocketNotifier *snHup;

    65     QSocketNotifier *snTerm;

    66 };

    67 //! [0]

    68 

    69 

    70 //! [1]

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

    72     	 : QObject(parent,name)

    73 {

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

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

    76 

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

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

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

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

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

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

    83 

    84     ...

    85 }

    86 //! [1]

    87 

    88 

    89 //! [2]

    90 static int setup_unix_signal_handlers()

    91 {

    92     struct sigaction hup, term;

    93 

    94     hup.sa_handler = MyDaemon::hupSignalHandler;

    95     sigemptyset(&hup.sa_mask);

    96     hup.sa_flags = 0;

    97     hup.sa_flags |= SA_RESTART;

    98 

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

   100        return 1;

   101 

   102     term.sa_handler = MyDaemon::termSignalHandler;

   103     sigemptyset(&term.sa_mask);

   104     term.sa_flags |= SA_RESTART;

   105 

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

   107        return 2;

   108 

   109     return 0;

   110 }

   111 //! [2]

   112 

   113 

   114 //! [3]

   115 void MyDaemon::hupSignalHandler(int)

   116 {

   117     char a = 1;

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

   119 }

   120 

   121 void MyDaemon::termSignalHandler(int)

   122 {

   123     char a = 1;

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

   125 }

   126 //! [3]

   127 

   128 

   129 //! [4]

   130 void MyDaemon::handleSigTerm()

   131 {

   132     snTerm->setEnabled(false);

   133     char tmp;

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

   135 

   136     // do Qt stuff

   137 

   138     snTerm->setEnabled(true);

   139 }

   140 

   141 void MyDaemon::handleSigHup()

   142 {

   143     snHup->setEnabled(false);

   144     char tmp;

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

   146 

   147     // do Qt stuff

   148 

   149     snHup->setEnabled(true);

   150 }

   151 //! [4]