# Poco::Net

# class StreamSocket

Library: Net
Package: Sockets
Header: Poco/Net/StreamSocket.h

## Description

This class provides an interface to a TCP stream socket.

## Inheritance

Direct Base Classes: Socket

All Base Classes: Socket

Known Derived Classes: DialogSocket, WebSocket, SecureStreamSocket

## Member Summary

Member Functions: bind, connect, connectNB, operator =, receiveBytes, sendBytes, sendFile, sendUrgent, shutdown, shutdownReceive, shutdownSend

Inherited Functions: address, available, close, destroyBufVec, error, fromFileDescriptor, getBlocking, getError, getKeepAlive, getLinger, getNoDelay, getOOBInline, getOption, getReceiveBufferSize, getReceiveTimeout, getReuseAddress, getReusePort, getSendBufferSize, getSendTimeout, impl, init, isDatagram, isNull, isRaw, isStream, lastError, lastErrorDesc, makeBufVec, makeBuffer, operator !=, operator <, operator <=, operator =, operator ==, operator >, operator >=, peerAddress, poll, secure, select, setBlocking, setKeepAlive, setLinger, setNoDelay, setOOBInline, setOption, setReceiveBufferSize, setReceiveTimeout, setReuseAddress, setReusePort, setSendBufferSize, setSendTimeout, sockfd, supportsIPv4, supportsIPv6, type

## Constructors

### StreamSocket

StreamSocket();

Creates an unconnected stream socket.

Before sending or receiving data, the socket must be connected with a call to connect().

### StreamSocket

explicit StreamSocket(
const SocketAddress & address
);

Creates a stream socket and connects it to the socket specified by address.

### StreamSocket

explicit StreamSocket(
SocketAddress::Family family
);

Creates an unconnected stream socket for the given address family.

This is useful if certain socket options (like send and receive buffer) sizes, that must be set before connecting the socket, will be set later on.

### StreamSocket

StreamSocket(
const Socket & socket
);

Creates the StreamSocket with the SocketImpl from another socket. The SocketImpl must be a StreamSocketImpl, otherwise an InvalidArgumentException will be thrown.

### StreamSocket

StreamSocket(
const StreamSocket & socket
);

Creates the StreamSocket with the SocketImpl from another socket.

### StreamSocket

StreamSocket(
SocketImpl * pImpl
);

Creates the Socket and attaches the given SocketImpl. The socket takes ownership of the SocketImpl.

The SocketImpl must be a StreamSocketImpl, otherwise an InvalidArgumentException will be thrown.

## Destructor

### ~StreamSocket

~StreamSocket() override;

Destroys the StreamSocket.

## Member Functions

### bind

void bind(
const SocketAddress & address,
bool reuseAddress = false,
bool ipV6Only = false
);

Bind a local address to the socket.

This is usually only done when establishing a server socket.

TCP clients normally do not bind to a local address, but in some special advanced cases it may be useful to have this type of functionality. (e.g. in multihoming situations where the traffic will be sent through a particular interface; or in computer clustered environments with active/standby servers and it is desired to make the traffic from either active host present the same source IP address).

Note: Practical use of client source IP address binding

    may require OS networking setup outside the scope of
    the Poco library.

If reuseAddress is true, sets the SO_REUSEADDR socket option.

### connect

void connect(
const SocketAddress & address
);

Initializes the socket and establishes a connection to the TCP server at the given address.

Can also be used for UDP sockets. In this case, no connection is established. Instead, incoming and outgoing packets are restricted to the specified address.

### connect

void connect(
const SocketAddress & address,
const Poco::Timespan & timeout
);

Initializes the socket, sets the socket timeout and establishes a connection to the TCP server at the given address.

### connectNB

void connectNB(
const SocketAddress & address
);

Initializes the socket and establishes a connection to the TCP server at the given address. Prior to opening the connection the socket is set to nonblocking mode.

### operator =

StreamSocket & operator = (
const Socket & socket
);

Assignment operator.

Releases the socket's SocketImpl and attaches the SocketImpl from the other socket and increments the reference count of the SocketImpl.

### operator =

StreamSocket & operator = (
const StreamSocket & socket
);

Assignment operator.

Releases the socket's SocketImpl and attaches the SocketImpl from the other socket and increments the reference count of the SocketImpl.

### receiveBytes

int receiveBytes(
void * buffer,
int length,
int flags = 0
);

Receives data from the socket and stores it in buffer. Up to length bytes are received.

Returns the number of bytes received. A return value of 0 means a graceful shutdown of the connection from the peer.

Throws a TimeoutException if a receive timeout has been set and nothing is received within that interval. Throws a NetException (or a subclass) in case of other errors.

The flags parameter can be used to pass system-defined flags for recv() like MSG_OOB, MSG_PEEK or MSG_WAITALL.

### receiveBytes

int receiveBytes(
SocketBufVec & buffer,
int flags = 0
);

Receives data from the socket and stores it in buffers.

Returns the number of bytes received.

The flags parameter can be used to pass system-defined flags for recv() like MSG_OOB, MSG_PEEK or MSG_WAITALL.

### receiveBytes

int receiveBytes(
Poco::Buffer < char > & buffer,
int flags = 0,
const Poco::Timespan & timeout = 100000
);

Receives data from the socket and stores it in buffers.

Returns the number of bytes received.

The flags parameter can be used to pass system-defined flags for recv() like MSG_OOB, MSG_PEEK or MSG_WAITALL.

### receiveBytes

int receiveBytes(
Poco::FIFOBuffer & buffer
);

Receives data from the socket and stores it in buffer. Up to length bytes are received. FIFOBuffer has writable/readable transition notifications which may be enabled to notify the caller when the buffer transitions between empty, partially full and full states.

Returns the number of bytes received. A return value of 0 means a graceful shutdown of the connection from the peer.

Throws a TimeoutException if a receive timeout has been set and nothing is received within that interval. Throws a NetException (or a subclass) in case of other errors.

### sendBytes

int sendBytes(
const void * buffer,
int length,
int flags = 0
);

Sends the contents of the given buffer through the socket.

Returns the number of bytes sent, which may be less than the number of bytes specified.

Certain socket implementations may also return a negative value denoting a certain condition.

The flags parameter can be used to pass system-defined flags for send() like MSG_OOB.

### sendBytes

int sendBytes(
const SocketBufVec & buffer,
int flags = 0
);

Sends the contents of the given buffers through the socket.

Returns the number of bytes sent, which may be less than the number of bytes specified.

The flags parameter can be used to pass system-defined flags for send() like MSG_OOB.

### sendBytes

int sendBytes(
Poco::FIFOBuffer & buffer
);

Sends the contents of the given buffer through the socket. FIFOBuffer has writable/readable transition notifications which may be enabled to notify the caller when the buffer transitions between empty, partially full and full states.

Returns the number of bytes sent, which may be less than the number of bytes specified.

Certain socket implementations may also return a negative value denoting a certain condition.

The flags parameter can be used to pass system-defined flags for send() like MSG_OOB.

### sendFile

std::streamsize sendFile(
Poco::FileInputStream & FileInputStream,
std::streamoff offset = 0,
std::streamsize count = 0
);

Sends the contents of a file over the socket, using operating system-specific APIs, if available. The socket must not have been set to non-blocking.

If count is != 0, sends the given number of bytes, otherwise sends all bytes, starting from the given offset.

On Linux, macOS and FreeBSD systems, the implementation uses sendfile() or sendfile64(). On Windows, the implementation uses TransmitFile().

If neither sendfile() nor TransmitFile() is available, or the socket is a SecureStreamSocket (secure() returne true), falls back to reading the file block by block and calling sendBytes().

Returns the number of bytes sent, which should be the same as count, unless count is 0.

Throws NetException (or a subclass) in case of any errors. Also throws a NetException if the socket has been set to non-blocking.

### sendUrgent

void sendUrgent(
unsigned char data
);

Sends one byte of urgent data through the socket.

The data is sent with the MSG_OOB flag.

The preferred way for a socket to receive urgent data is by enabling the SO_OOBINLINE option.

### shutdown

int shutdown();

Shuts down both the receiving and the sending part of the socket connection.

Returns 0 for a non-blocking socket. May return a negative value for a non-blocking socket in case of a TLS connection. In that case, the operation should be retried once the underlying socket becomes writable.

### shutdownReceive

void shutdownReceive();

Shuts down the receiving part of the socket connection.

### shutdownSend

int shutdownSend();

Shuts down the sending part of the socket connection.

Returns 0 for a non-blocking socket. May return a negative value for a non-blocking socket in case of a TLS connection. In that case, the operation should be retried once the underlying socket becomes writable.