QUdpSocket#
The QUdpSocket
class provides a UDP socket. More…
Synopsis#
Functions#
def
bind
(addr[, port=0[, mode=QAbstractSocket.BindFlag.DefaultForPlatform]])def
hasPendingDatagrams
()def
joinMulticastGroup
(groupAddress)def
joinMulticastGroup
(groupAddress, iface)def
leaveMulticastGroup
(groupAddress)def
leaveMulticastGroup
(groupAddress, iface)def
multicastInterface
()def
pendingDatagramSize
()def
readDatagram
(, maxlen)def
receiveDatagram
([maxSize=-1])def
setMulticastInterface
(iface)def
writeDatagram
(datagram, host, port)def
writeDatagram
(datagram)
Note
This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE
Detailed Description#
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
UDP (User Datagram Protocol) is a lightweight, unreliable, datagram-oriented, connectionless protocol. It can be used when reliability isn’t important. QUdpSocket
is a subclass of QAbstractSocket
that allows you to send and receive UDP datagrams.
The most common way to use this class is to bind to an address and port using bind()
, then call writeDatagram()
and readDatagram()
/ receiveDatagram()
to transfer data. If you want to use the standard QIODevice functions read(), readLine(), write(), etc., you must first connect the socket directly to a peer by calling connectToHost()
.
The socket emits the bytesWritten() signal every time a datagram is written to the network. If you just want to send datagrams, you don’t need to call bind()
.
The readyRead() signal is emitted whenever datagrams arrive. In that case, hasPendingDatagrams()
returns true
. Call pendingDatagramSize()
to obtain the size of the first pending datagram, and readDatagram()
or receiveDatagram()
to read it.
Note
An incoming datagram should be read when you receive the readyRead() signal, otherwise this signal will not be emitted for the next datagram.
Example:
def initSocket(self): udpSocket = QUdpSocket(self) udpSocket.bind(QHostAddress.LocalHost, 7755) udpSocket.readyRead.connect( self.readPendingDatagrams) def readPendingDatagrams(self): while udpSocket.hasPendingDatagrams(): datagram = udpSocket.receiveDatagram() processTheDatagram(datagram)
QUdpSocket
also supports UDP multicast. Use joinMulticastGroup()
and leaveMulticastGroup()
to control group membership, and MulticastTtlOption
and MulticastLoopbackOption
to set the TTL and loopback socket options. Use setMulticastInterface()
to control the outgoing interface for multicast datagrams, and multicastInterface()
to query it.
With QUdpSocket
, you can also establish a virtual connection to a UDP server using connectToHost()
and then use read() and write() to exchange datagrams without specifying the receiver for each datagram.
The Broadcast Sender , Broadcast Receiver , Multicast Sender , and Multicast Receiver examples illustrate how to use QUdpSocket
in applications.
See also
- class PySide6.QtNetwork.QUdpSocket([parent=None])#
- Parameters:
parent –
PySide6.QtCore.QObject
Creates a QUdpSocket
object.
parent
is passed to the QObject constructor.
See also
- PySide6.QtNetwork.QUdpSocket.bind(addr[, port=0[, mode=QAbstractSocket.BindFlag.DefaultForPlatform]])#
- Parameters:
addr –
SpecialAddress
port – int
mode – Combination of
QAbstractSocket.BindFlag
- Return type:
bool
- PySide6.QtNetwork.QUdpSocket.hasPendingDatagrams()#
- Return type:
bool
Returns true
if at least one datagram is waiting to be read; otherwise returns false
.
See also
- PySide6.QtNetwork.QUdpSocket.joinMulticastGroup(groupAddress)#
- Parameters:
groupAddress –
PySide6.QtNetwork.QHostAddress
- Return type:
bool
Joins the multicast group specified by groupAddress
on the default interface chosen by the operating system. The socket must be in BoundState, otherwise an error occurs.
Note that if you are attempting to join an IPv4 group, your socket must not be bound using IPv6 (or in dual mode, using Any
). You must use AnyIPv4
instead.
This function returns true
if successful; otherwise it returns false
and sets the socket error accordingly.
Note
Joining IPv6 multicast groups without an interface selection is not supported in all operating systems. Consider using the overload where the interface is specified.
See also
- PySide6.QtNetwork.QUdpSocket.joinMulticastGroup(groupAddress, iface)
- Parameters:
groupAddress –
PySide6.QtNetwork.QHostAddress
- Return type:
bool
This is an overloaded function.
Joins the multicast group address groupAddress
on the interface iface
.
See also
- PySide6.QtNetwork.QUdpSocket.leaveMulticastGroup(groupAddress)#
- Parameters:
groupAddress –
PySide6.QtNetwork.QHostAddress
- Return type:
bool
Leaves the multicast group specified by groupAddress
on the default interface chosen by the operating system. The socket must be in BoundState, otherwise an error occurs.
This function returns true
if successful; otherwise it returns false
and sets the socket error accordingly.
Note
This function should be called with the same arguments as were passed to joinMulticastGroup()
.
See also
- PySide6.QtNetwork.QUdpSocket.leaveMulticastGroup(groupAddress, iface)
- Parameters:
groupAddress –
PySide6.QtNetwork.QHostAddress
- Return type:
bool
This is an overloaded function.
Leaves the multicast group specified by groupAddress
on the interface iface
.
Note
This function should be called with the same arguments as were passed to joinMulticastGroup()
.
See also
- PySide6.QtNetwork.QUdpSocket.multicastInterface()#
- Return type:
Returns the interface for the outgoing interface for multicast datagrams. This corresponds to the IP_MULTICAST_IF socket option for IPv4 sockets and the IPV6_MULTICAST_IF socket option for IPv6 sockets. If no interface has been previously set, this function returns an invalid QNetworkInterface
. The socket must be in BoundState, otherwise an invalid QNetworkInterface
is returned.
See also
- PySide6.QtNetwork.QUdpSocket.pendingDatagramSize()#
- Return type:
int
Returns the size of the first pending UDP datagram. If there is no datagram available, this function returns -1.
See also
- PySide6.QtNetwork.QUdpSocket.readDatagram(maxlen)#
- Parameters:
maxlen – int
- Return type:
(data, address, port)
Receives a datagram no larger than maxSize
bytes and stores it in data
. The sender’s host address and port is stored in *``address`` and *``port`` (unless the pointers are None
).
Returns the size of the datagram on success; otherwise returns -1.
If maxSize
is too small, the rest of the datagram will be lost. To avoid loss of data, call pendingDatagramSize()
to determine the size of the pending datagram before attempting to read it. If maxSize
is 0, the datagram will be discarded.
- PySide6.QtNetwork.QUdpSocket.receiveDatagram([maxSize=-1])#
- Parameters:
maxSize – int
- Return type:
Receives a datagram no larger than maxSize
bytes and returns it in the QNetworkDatagram
object, along with the sender’s host address and port. If possible, this function will also try to determine the datagram’s destination address, port, and the number of hop counts at reception time.
On failure, returns a QNetworkDatagram
that reports not valid
.
If maxSize
is too small, the rest of the datagram will be lost. If maxSize
is 0, the datagram will be discarded. If maxSize
is -1 (the default), this function will attempt to read the entire datagram.
- PySide6.QtNetwork.QUdpSocket.setMulticastInterface(iface)#
- Parameters:
Sets the outgoing interface for multicast datagrams to the interface iface
. This corresponds to the IP_MULTICAST_IF socket option for IPv4 sockets and the IPV6_MULTICAST_IF socket option for IPv6 sockets. The socket must be in BoundState, otherwise this function does nothing.
- PySide6.QtNetwork.QUdpSocket.writeDatagram(datagram, host, port)#
- Parameters:
datagram –
PySide6.QtCore.QByteArray
port – int
- Return type:
int
This is an overloaded function.
Sends the datagram datagram
to the host address host
and at port port
.
The function returns the number of bytes sent if it succeeded or -1 if it encountered an error.
- PySide6.QtNetwork.QUdpSocket.writeDatagram(datagram)
- Parameters:
datagram –
PySide6.QtNetwork.QNetworkDatagram
- Return type:
int
This is an overloaded function.
Sends the datagram datagram
to the host address and port numbers contained in datagram
, using the network interface and hop count limits also set there. If the destination address and port numbers are unset, this function will send to the address that was passed to connectToHost()
.
If the destination address is IPv6 with a non-empty scope id
but differs from the interface index in datagram
, it is undefined which interface the operating system will choose to send on.
The function returns the number of bytes sent if it succeeded or -1 if it encountered an error.
Warning
Calling this function on a connected UDP socket may result in an error and no packet being sent. If you are using a connected socket, use write() to send datagrams.