C++ Q_CHECK_TYPE函数代码示例

/*! \since 4.8 */
bool QNativeSocketEngine::setMulticastInterface(const QNetworkInterface &iface)
{
    Q_D(QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::setMulticastInterface(), false);
    Q_CHECK_TYPE(QNativeSocketEngine::setMulticastInterface(), QAbstractSocket::UdpSocket, false);
    return d->nativeSetMulticastInterface(iface);
}

/*!
    Writes a UDP datagram of size \a size bytes to the socket from
    \a data to the address \a host on port \a port, and returns the
    number of bytes written, or -1 if an error occurred.

    Only one datagram is sent, and if there is too much data to fit
    into a single datagram, the operation will fail and error()
    will return QAbstractSocket::DatagramTooLargeError. Operating systems impose an
    upper limit to the size of a datagram, but this size is different
    on almost all platforms. Sending large datagrams is in general
    disadvised, as even if they are sent successfully, they are likely
    to be fragmented before arriving at their destination.

    Experience has shown that it is in general safe to send datagrams
    no larger than 512 bytes.

    \sa readDatagram()
*/
qint64 QNativeSocketEngine::writeDatagram(const char *data, qint64 size,
                                       const QHostAddress &host, quint16 port)
{
    Q_D(QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::writeDatagram(), -1);
    Q_CHECK_TYPE(QNativeSocketEngine::writeDatagram(), QAbstractSocket::UdpSocket, -1);
    return d->nativeSendDatagram(data, size, host, port);
}

/*!
    Returns the size of the pending datagram, or -1 if no datagram is
    pending. A datagram size of 0 is perfectly valid. This function is
    called by UDP sockets before receiveMessage(). For TCP sockets,
    call bytesAvailable().
*/
qint64 QNativeSocketEngine::pendingDatagramSize() const
{
    Q_D(const QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::pendingDatagramSize(), -1);
    Q_CHECK_TYPE(QNativeSocketEngine::pendingDatagramSize(), QAbstractSocket::UdpSocket, false);

    return d->nativePendingDatagramSize();
}

/*!
    Writes a UDP datagram of size \a size bytes to the socket from
    \a data to the destination contained in \a header, and returns the
    number of bytes written, or -1 if an error occurred. If \a header
    contains other settings like hop limit or source address, this function
    will try to pass them to the operating system too, but will not
    indicate an error if it could not pass them.

    Only one datagram is sent, and if there is too much data to fit
    into a single datagram, the operation will fail and error()
    will return QAbstractSocket::DatagramTooLargeError. Operating systems impose an
    upper limit to the size of a datagram, but this size is different
    on almost all platforms. Sending large datagrams is in general
    disadvised, as even if they are sent successfully, they are likely
    to be fragmented before arriving at their destination.

    Experience has shown that it is in general safe to send IPv4 datagrams
    no larger than 512 bytes or IPv6 datagrams no larger than 1280 (the
    minimum MTU).

    \sa readDatagram()
*/
qint64 QNativeSocketEngine::writeDatagram(const char *data, qint64 size, const QIpPacketHeader &header)
{
    Q_D(QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::writeDatagram(), -1);
    Q_CHECK_TYPE(QNativeSocketEngine::writeDatagram(), QAbstractSocket::UdpSocket, -1);

    return d->nativeSendDatagram(data, size, header);
}

/*!
    Reads up to \a maxSize bytes of a datagram from the socket,
    stores it in \a data and returns the number of bytes read. The
    address and port of the sender are stored in \a address and \a
    port. If either of these pointers is 0, the corresponding value is
    discarded.

    To avoid unnecessarily loss of data, call pendingDatagramSize() to
    determine the size of the pending message before reading it. If \a
    maxSize is too small, the rest of the datagram will be lost.

    Returns -1 if an error occurred.

    \sa hasPendingDatagrams()
*/
qint64 QNativeSocketEngine::readDatagram(char *data, qint64 maxSize, QHostAddress *address,
                                      quint16 *port)
{
    Q_D(QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::readDatagram(), -1);
    Q_CHECK_TYPE(QNativeSocketEngine::readDatagram(), QAbstractSocket::UdpSocket, false);

    return d->nativeReceiveDatagram(data, maxSize, address, port);
}

/*!
    Returns true if there is at least one datagram pending. This
    function is only called by UDP sockets, where a datagram can have
    a size of 0. TCP sockets call bytesAvailable().
*/
bool QNativeSocketEngine::hasPendingDatagrams() const
{
    Q_D(const QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::hasPendingDatagrams(), false);
    Q_CHECK_NOT_STATE(QNativeSocketEngine::hasPendingDatagrams(), QAbstractSocket::UnconnectedState, false);
    Q_CHECK_TYPE(QNativeSocketEngine::hasPendingDatagrams(), QAbstractSocket::UdpSocket, false);

    return d->nativeHasPendingDatagrams();
}

/*!
    Accepts a pending connection from the socket, which must be in
    ListeningState, and returns its socket descriptor. If no pending
    connections are available, -1 is returned.

    \sa bind(), listen()
*/
int QNativeSocketEngine::accept()
{
    Q_D(QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::accept(), -1);
    Q_CHECK_STATE(QNativeSocketEngine::accept(), QAbstractSocket::ListeningState, false);
    Q_CHECK_TYPE(QNativeSocketEngine::accept(), QAbstractSocket::TcpSocket, false);

    return d->nativeAccept();
}

/*!
    Reads up to \a maxSize bytes of a datagram from the socket,
    stores it in \a data and returns the number of bytes read. The
    address, port, and other IP header fields are stored in \a header
    according to the request in \a options.

    To avoid unnecessarily loss of data, call pendingDatagramSize() to
    determine the size of the pending message before reading it. If \a
    maxSize is too small, the rest of the datagram will be lost.

    Returns -1 if an error occurred.

    \sa hasPendingDatagrams()
*/
qint64 QNativeSocketEngine::readDatagram(char *data, qint64 maxSize, QIpPacketHeader *header,
                                         PacketHeaderOptions options)
{
    Q_D(QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::readDatagram(), -1);
    Q_CHECK_TYPE(QNativeSocketEngine::readDatagram(), QAbstractSocket::UdpSocket, -1);

    return d->nativeReceiveDatagram(data, maxSize, header, options);
}

/*!
    \since 4.8
*/
bool QNativeSocketEngine::joinMulticastGroup(const QHostAddress &groupAddress,
                                             const QNetworkInterface &iface)
{
    Q_D(QNativeSocketEngine);
    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::joinMulticastGroup(), false);
    Q_CHECK_STATE(QNativeSocketEngine::joinMulticastGroup(), QAbstractSocket::BoundState, false);
    Q_CHECK_TYPE(QNativeSocketEngine::joinMulticastGroup(), QAbstractSocket::UdpSocket, false);

    // if the user binds a socket to an IPv6 address (or QHostAddress::Any) and
    // then attempts to join an IPv4 multicast group, this won't work on
    // Windows. In order to make this cross-platform, we warn & fail on all
    // platforms.
    if (groupAddress.protocol() == QAbstractSocket::IPv4Protocol &&
        (d->socketProtocol == QAbstractSocket::IPv6Protocol ||
         d->socketProtocol == QAbstractSocket::AnyIPProtocol)) {
        qWarning("QAbstractSocket: cannot bind to QHostAddress::Any (or an IPv6 address) and join an IPv4 multicast group;"
                 " bind to QHostAddress::AnyIPv4 instead if you want to do this");
        return false;
    }

    return d->nativeJoinMulticastGroup(groupAddress, iface);
}