QNetworkInterface Class

Member Function Documentation

QNetworkInterface::QNetworkInterface()

Constructs an empty network interface object.

QNetworkInterface::QNetworkInterface(const QNetworkInterface &other)

Creates a copy of the QNetworkInterface object contained in other.

[noexcept] QNetworkInterface::~QNetworkInterface()

Frees the resources associated with the QNetworkInterface object.

QList<QNetworkAddressEntry> QNetworkInterface::addressEntries() const

Returns the list of IP addresses that this interface possesses along with their associated netmasks and broadcast addresses.

If the netmask or broadcast address or other information is not necessary, you can call the allAddresses() function to obtain just the IP addresses of the active interfaces.

[static] QList<QHostAddress> QNetworkInterface::allAddresses()

This convenience function returns all IP addresses found on the host machine. It is equivalent to calling addressEntries() on all the objects returned by allInterfaces() that are in the QNetworkInterface::IsUp state to obtain lists of QNetworkAddressEntry objects then calling QNetworkAddressEntry::ip() on each of these.

[static] QList<QNetworkInterface> QNetworkInterface::allInterfaces()

Returns a listing of all the network interfaces found on the host machine. In case of failure it returns a list with zero elements.

QNetworkInterface::InterfaceFlags QNetworkInterface::flags() const

Returns the flags associated with this network interface.

QString QNetworkInterface::hardwareAddress() const

Returns the low-level hardware address for this interface. On Ethernet interfaces, this will be a MAC address in string representation, separated by colons.

Other interface types may have other types of hardware addresses. Implementations should not depend on this function returning a valid MAC address.

See also type().

QString QNetworkInterface::humanReadableName() const

Returns the human-readable name of this network interface on Windows, such as "Local Area Connection", if the name could be determined. If it couldn't, this function returns the same as name(). The human-readable name is a name that the user can modify in the Windows Control Panel, so it may change during the execution of the program.

On Unix, this function currently always returns the same as name(), since Unix systems don't store a configuration for human-readable names.

int QNetworkInterface::index() const

Returns the interface system index, if known. This is an integer assigned by the operating system to identify this interface and it generally doesn't change. It matches the scope ID field in IPv6 addresses.

If the index isn't known, this function returns 0.

[static] QNetworkInterface QNetworkInterface::interfaceFromIndex(int index)

Returns a QNetworkInterface object for the interface whose internal ID is index. Network interfaces have a unique identifier called the "interface index" to distinguish it from other interfaces on the system. Often, this value is assigned progressively and interfaces being removed and then added again get a different value every time.

This index is also found in the IPv6 address' scope ID field.

[static] QNetworkInterface QNetworkInterface::interfaceFromName(const QString &name)

Returns a QNetworkInterface object for the interface named name. If no such interface exists, this function returns an invalid QNetworkInterface object.

The string name may be either an actual interface name (such as "eth0" or "en1") or an interface index in string form ("1", "2", etc.).

See also name() and isValid().

[static] int QNetworkInterface::interfaceIndexFromName(const QString &name)

Returns the index of the interface whose name is name or 0 if there is no interface with that name. This function should produce the same result as the following code, but will probably execute faster.

    QNetworkInterface::interfaceFromName(name).index()

See also interfaceFromName(), interfaceNameFromIndex(), and QNetworkDatagram::interfaceIndex().

[static] QString QNetworkInterface::interfaceNameFromIndex(int index)

Returns the name of the interface whose index is index or an empty string if there is no interface with that index. This function should produce the same result as the following code, but will probably execute faster.

    QNetworkInterface::interfaceFromIndex(index).name()

See also interfaceFromIndex(), interfaceIndexFromName(), and QNetworkDatagram::interfaceIndex().

bool QNetworkInterface::isValid() const

Returns true if this QNetworkInterface object contains valid information about a network interface.

int QNetworkInterface::maximumTransmissionUnit() const

Returns the maximum transmission unit on this interface, if known, or 0 otherwise.

The maximum transmission unit is the largest packet that may be sent on this interface without incurring link-level fragmentation. Applications may use this value to calculate the size of the payload that will fit an unfragmented UDP datagram. Remember to subtract the sizes of headers used in your communication over the interface, e.g. TCP (20 bytes) or UDP (12), IPv4 (20) or IPv6 (40, absent some form of header compression), when computing how big a payload you can transmit. Also note that the MTU along the full path (the Path MTU) to the destination may be smaller than the interface's MTU.

See also QUdpSocket.

QString QNetworkInterface::name() const

Returns the name of this network interface. On Unix systems, this is a string containing the type of the interface and optionally a sequence number, such as "eth0", "lo" or "pcn0". On Windows, it's an internal ID that cannot be changed by the user.

[noexcept] void QNetworkInterface::swap(QNetworkInterface &other)

Swaps this network interface instance with other. This function is very fast and never fails.

QNetworkInterface::InterfaceType QNetworkInterface::type() const

Returns the type of this interface, if it could be determined. If it could not be determined, this function returns QNetworkInterface::Unknown.

See also hardwareAddress().

QNetworkInterface &QNetworkInterface::operator=(const QNetworkInterface &other)

Copies the contents of the QNetworkInterface object contained in other into this one.