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std.socket

Example:
See /dmd/samples/d/listener.d and /dmd/samples/d/htmlget.d

License:
Boost License 1.0.

Authors:
Christopher E. Miller, David Nadlinger, Vladimir Panteleev

Source:
std/socket.d

class SocketException: object.Exception;
Base exception thrown by std.socket.

this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null);

this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__);

@property string lastSocketError();
Retrieve the error message for the most recently encountered network error.

class SocketOSException: std.socket.SocketException;
Socket exceptions representing network errors reported by the operating system.

int errorCode;
Platform-specific error code.

this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null, int err = _lasterr(), string function(int) errorFormatter = &formatSocketError);

this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__, int err = _lasterr(), string function(int) errorFormatter = &formatSocketError);

this(string msg, int err, string function(int) errorFormatter = &formatSocketError, string file = __FILE__, size_t line = __LINE__, Throwable next = null);

class SocketParameterException: std.socket.SocketException;
Socket exceptions representing invalid parameters specified by user code.

this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null);

this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__);

class SocketFeatureException: std.socket.SocketException;
Socket exceptions representing attempts to use network capabilities not available on the current system.

this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null);

this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__);

bool wouldHaveBlocked();
Return true if the last socket operation failed because the socket was in non-blocking mode and the operation would have blocked.

enum AddressFamily: int;
The communication domain used to resolve an address.

UNSPEC
Unspecified address family

UNIX
Local communication

INET
Internet Protocol version 4

IPX
Novell IPX

APPLETALK
AppleTalk

INET6
Internet Protocol version 6

enum SocketType: int;
Communication semantics

STREAM
Sequenced, reliable, two-way communication-based byte streams

DGRAM
Connectionless, unreliable datagrams with a fixed maximum length; data may be lost or arrive out of order

RAW
Raw protocol access

RDM
Reliably-delivered message datagrams

SEQPACKET
Sequenced, reliable, two-way connection-based datagrams with a fixed maximum length

enum ProtocolType: int;
Protocol

IP
Internet Protocol version 4

ICMP
Internet Control Message Protocol

IGMP
Internet Group Management Protocol

GGP
Gateway to Gateway Protocol

TCP
Transmission Control Protocol

PUP
PARC Universal Packet Protocol

UDP
User Datagram Protocol

IDP
Xerox NS protocol

RAW
Raw IP packets

IPV6
Internet Protocol version 6

class Protocol;
Protocol is a class for retrieving protocol information.

Example:
auto proto = new Protocol;
writeln("About protocol TCP:");
if (proto.getProtocolByType(ProtocolType.TCP))
{
    writefln("  Name: %s", proto.name);
    foreach(string s; proto.aliases)
         writefln("  Alias: %s", s);
}
else
    writeln("  No information found");

ProtocolType type;
string name;
string[] aliases;
These members are populated when one of the following functions are called successfully:

bool getProtocolByName(in char[] name);
Returns:
false on failure

bool getProtocolByType(ProtocolType type);
Returns:
false on failure

class Service;
Service is a class for retrieving service information.

Example:
auto serv = new Service;
writeln("About service epmap:");
if (serv.getServiceByName("epmap", "tcp"))
{
    writefln("  Service: %s", serv.name);
    writefln("  Port: %d", serv.port);
    writefln("  Protocol: %s", serv.protocolName);
    foreach (string s; serv.aliases)
         writefln("  Alias: %s", s);
}
else
    writefln("  No service for epmap.");

string name;
string[] aliases;
ushort port;
string protocolName;
These members are populated when one of the following functions are called successfully:

bool getServiceByName(in char[] name, in char[] protocolName = null);
bool getServiceByPort(ushort port, in char[] protocolName = null);
If a protocol name is omitted, any protocol will be matched.

Returns:
false on failure.

class HostException: std.socket.SocketOSException;
Class for exceptions thrown from an InternetHost.

this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null, int err = _lasterr());

this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__, int err = _lasterr());

this(string msg, int err, string file = __FILE__, size_t line = __LINE__, Throwable next = null);

class InternetHost;
InternetHost is a class for resolving IPv4 addresses.

Consider using getAddress, parseAddress and Address methods instead of using this class directly.

Example:
auto ih = new InternetHost;

// Forward lookup
writeln("About www.digitalmars.com:");
if (ih.getHostByName("www.digitalmars.com"))
{
    writefln("  Name: %s", ih.name);
    auto ip = InternetAddress.addrToString(ih.addrList[0]);
    writefln("  IP address: %s", ip);
    foreach (string s; ih.aliases)
         writefln("  Alias: %s", s);
    writeln("---");

    // Reverse lookup
    writefln("About IP %s:", ip);
    if (ih.getHostByAddr(ih.addrList[0]))
    {
        writefln("  Name: %s", ih.name);
        foreach (string s; ih.aliases)
             writefln("  Alias: %s", s);
    }
    else
        writeln("  Reverse lookup failed");
}
else
    writeln("  Can't resolve www.digitalmars.com");

string name;
string[] aliases;
uint[] addrList;
These members are populated when one of the following functions are called successfully:

bool getHostByName(in char[] name);
Resolve host name.

Returns:
false if unable to resolve.

bool getHostByAddr(uint addr);
Resolve IPv4 address number.

Parameters:
uint addr The IPv4 address to resolve, in host byte order.

Returns:
false if unable to resolve.

bool getHostByAddr(in char[] addr);
Same as previous, but addr is an IPv4 address string in the dotted-decimal form a.b.c.d.

Returns:
false if unable to resolve.

struct AddressInfo;
Holds information about a socket address retrieved by getAddressInfo.

AddressFamily family;
Address family

SocketType type;
Socket type

ProtocolType protocol;
Protocol

Address address;
Socket address

string canonicalName;
Canonical name, when AddressInfoFlags.CANONNAME is used.

enum AddressInfoFlags: int;
Specifies option flags for getAddressInfo.

PASSIVE
The resulting addresses will be used in a call to Socket.bind.

CANONNAME
The canonical name is returned in canonicalName member in the first AddressInfo.

NUMERICHOST
The node parameter passed to getAddressInfo must be a numeric string. This will suppress any potentially lengthy network host address lookups.

AddressInfo[] getAddressInfo(T...)(in char[] node, T options);
Provides protocol-independent translation from host names to socket addresses. If advanced functionality is not required, consider using getAddress for compatibility with older systems.

Returns:
Array with one AddressInfo per socket address.

Throws:
SocketOSException on failure, or SocketFeatureException if this functionality is not available on the current system.

Parameters:
char[] node string containing host name or numeric address
T options optional additional parameters, identified by type:
  • string - service name or port number
  • AddressInfoFlags - option flags
  • AddressFamily - address family to filter by
  • SocketType - socket type to filter by
  • ProtocolType - protocol to filter by

Example:
// Roundtrip DNS resolution
auto results = getAddressInfo("www.digitalmars.com");
assert(results[0].address.toHostNameString() ==
    "digitalmars.com");

// Canonical name
results = getAddressInfo("www.digitalmars.com",
    AddressInfoFlags.CANONNAME);
assert(results[0].canonicalName == "digitalmars.com");

// IPv6 resolution
results = getAddressInfo("ipv6.google.com");
assert(results[0].family == AddressFamily.INET6);

// Multihomed resolution
results = getAddressInfo("google.com");
assert(results.length > 1);

// Parsing IPv4
results = getAddressInfo("127.0.0.1",
    AddressInfoFlags.NUMERICHOST);
assert(results.length && results[0].family ==
    AddressFamily.INET);

// Parsing IPv6
results = getAddressInfo("::1",
    AddressInfoFlags.NUMERICHOST);
assert(results.length && results[0].family ==
    AddressFamily.INET6);

Address[] getAddress(in char[] hostname, in char[] service = null);
Address[] getAddress(in char[] hostname, ushort port);
Provides protocol-independent translation from host names to socket addresses. Uses getAddressInfo if the current system supports it, and InternetHost otherwise.

Returns:
Array with one Address instance per socket address.

Throws:
SocketOSException on failure.

Example:
writeln("Resolving www.digitalmars.com:");
try
{
    auto addresses = getAddress("www.digitalmars.com");
    foreach (address; addresses)
        writefln("  IP: %s", address.toAddrString());
}
catch (SocketException e)
    writefln("  Lookup failed: %s", e.msg);

Address parseAddress(in char[] hostaddr, in char[] service = null);
Address parseAddress(in char[] hostaddr, ushort port);
Provides protocol-independent parsing of network addresses. Does not attempt name resolution. Uses getAddressInfo with AddressInfoFlags.NUMERICHOST if the current system supports it, and InternetAddress otherwise.

Returns:
An Address instance representing specified address.

Throws:
SocketException on failure.

Example:
writeln("Enter IP address:");
string ip = readln().chomp();
try
{
    Address address = parseAddress(ip);
    writefln("Looking up reverse of %s:",
        address.toAddrString());
    try
    {
        string reverse = address.toHostNameString();
        if (reverse)
            writefln("  Reverse name: %s", reverse);
        else
            writeln("  Reverse hostname not found.");
    }
    catch (SocketException e)
        writefln("  Lookup error: %s", e.msg);
}
catch (SocketException e)
{
    writefln("  %s is not a valid IP address: %s",
        ip, e.msg);
}

class AddressException: std.socket.SocketOSException;
Class for exceptions thrown from an Address.

this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null, int err = _lasterr());

this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__, int err = _lasterr());

this(string msg, int err, string file = __FILE__, size_t line = __LINE__, Throwable next = null);

abstract class Address;
Address is an abstract class for representing a socket addresses.

Example:
writeln("About www.google.com port 80:");
try
{
    Address[] addresses = getAddress("www.google.com", 80);
    writefln("  %d addresses found.", addresses.length);
    foreach (int i, Address a; addresses)
    {
        writefln("  Address %d:", i+1);
        writefln("    IP address: %s", a.toAddrString());
        writefln("    Hostname: %s", a.toHostNameString());
        writefln("    Port: %s", a.toPortString());
        writefln("    Service name: %s",
            a.toServiceNameString());
    }
}
catch (SocketException e)
    writefln("  Lookup error: %s", e.msg);

abstract @property sockaddr* name();
abstract const @property const(sockaddr)* name();
Returns pointer to underlying sockaddr structure.

abstract const @property socklen_t nameLen();
Returns actual size of underlying sockaddr structure.

const @property AddressFamily addressFamily();
Family of this address.

const string toAddrString();
Attempts to retrieve the host address as a human-readable string.

Throws:
AddressException on failure, or SocketFeatureException if address retrieval for this address family is not available on the current system.

const string toHostNameString();
Attempts to retrieve the host name as a fully qualified domain name.

Returns:
The FQDN corresponding to this Address, or null if the host name did not resolve.

Throws:
AddressException on error, or SocketFeatureException if host name lookup for this address family is not available on the current system.

const string toPortString();
Attempts to retrieve the numeric port number as a string.

Throws:
AddressException on failure, or SocketFeatureException if port number retrieval for this address family is not available on the current system.

const string toServiceNameString();
Attempts to retrieve the service name as a string.

Throws:
AddressException on failure, or SocketFeatureException if service name lookup for this address family is not available on the current system.

const string toString();
Human readable string representing this address.

class UnknownAddress: std.socket.Address;
UnknownAddress encapsulates an unknown socket address.

class UnknownAddressReference: std.socket.Address;
UnknownAddressReference encapsulates a reference to an arbitrary socket address.

this(sockaddr* sa, socklen_t len);
Constructs an Address with a reference to the specified sockaddr.

this(const(sockaddr)* sa, socklen_t len);
Constructs an Address with a copy of the specified sockaddr.

class InternetAddress: std.socket.Address;
InternetAddress encapsulates an IPv4 (Internet Protocol version 4) socket address.

Consider using getAddress, parseAddress and Address methods instead of using this class directly.

uint ADDR_ANY;
Any IPv4 host address.

uint ADDR_NONE;
An invalid IPv4 host address.

ushort PORT_ANY;
Any IPv4 port number.

const @property ushort port();
Returns the IPv4 port number (in host byte order).

const @property uint addr();
Returns the IPv4 address number (in host byte order).

this(in char[] addr, ushort port);
Construct a new InternetAddress.

Parameters:
char[] addr an IPv4 address string in the dotted-decimal form a.b.c.d, or a host name which will be resolved using an InternetHost object.
ushort port port number, may be PORT_ANY.

this(uint addr, ushort port);
this(ushort port);
Construct a new InternetAddress.

Parameters:
uint addr (optional) an IPv4 address in host byte order, may be ADDR_ANY.
ushort port port number, may be PORT_ANY.

const string toAddrString();
Human readable string representing the IPv4 address in dotted-decimal form.

const string toPortString();
Human readable string representing the IPv4 port.

const string toHostNameString();
Attempts to retrieve the host name as a fully qualified domain name.

Returns:
The FQDN corresponding to this InternetAddress, or null if the host name did not resolve.

Throws:
AddressException on error.

static uint parse(in char[] addr);
Parse an IPv4 address string in the dotted-decimal form a.b.c.d and return the number.

Returns:
If the string is not a legitimate IPv4 address, ADDR_NONE is returned.

static string addrToString(uint addr);
Convert an IPv4 address number in host byte order to a human readable string representing the IPv4 address in dotted-decimal form.

class Internet6Address: std.socket.Address;
Internet6Address encapsulates an IPv6 (Internet Protocol version 6) socket address.

Consider using getAddress, parseAddress and Address methods instead of using this class directly.

static @property ref const(ubyte)[16] ADDR_ANY();
Any IPv6 host address.

ushort PORT_ANY;
Any IPv6 port number.

const @property ushort port();
Returns the IPv6 port number.

const @property ubyte[16] addr();
Returns the IPv6 address.

this(in char[] addr, in char[] service = null);
Construct a new Internet6Address.

Parameters:
char[] addr an IPv6 host address string in the form described in RFC 2373, or a host name which will be resolved using getAddressInfo.
char[] service (optional) service name.

this(in char[] addr, ushort port);
Construct a new Internet6Address.

Parameters:
char[] addr an IPv6 host address string in the form described in RFC 2373, or a host name which will be resolved using getAddressInfo.
ushort port port number, may be PORT_ANY.

this(ubyte[16] addr, ushort port);
this(ushort port);
Construct a new Internet6Address.

Parameters:
ubyte[16] addr (optional) an IPv6 host address in host byte order, or ADDR_ANY.
ushort port port number, may be PORT_ANY.

static ubyte[16] parse(in char[] addr);
Parse an IPv6 host address string as described in RFC 2373, and return the address.

Throws:
SocketException on error.

abstract class UnixAddress: std.socket.Address;
UnixAddress encapsulates an address for a Unix domain socket (AF_UNIX). Available only on supported systems.

this(in char[] path);
Construct a new UnixAddress from the specified path.

const @property string path();
const string toString();
Get the underlying path.

class SocketAcceptException: std.socket.SocketOSException;
Class for exceptions thrown by Socket.accept.

this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null, int err = _lasterr());

this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__, int err = _lasterr());

this(string msg, int err, string file = __FILE__, size_t line = __LINE__, Throwable next = null);

enum SocketShutdown: int;
How a socket is shutdown:

RECEIVE
socket receives are disallowed

SEND
socket sends are disallowed

BOTH
both RECEIVE and SEND

enum SocketFlags: int;
Flags may be OR'ed together:

NONE
no flags specified

OOB
out-of-band stream data

PEEK
peek at incoming data without removing it from the queue, only for receiving

DONTROUTE
data should not be subject to routing; this flag may be ignored. Only for sending

struct TimeVal;
Duration timeout value.

tv_sec_t seconds;
Number of seconds.

tv_usec_t microseconds;
Number of additional microseconds.

class SocketSet;
A collection of sockets for use with Socket.select.

SocketSet allows specifying the capacity of the underlying fd_set, however users should be aware that the exact meaning of this value varies depending on the current platform:
  • On POSIX, fd_set is a bit array of file descriptors. The SocketSet capacity specifies the highest file descriptor which can be stored in the set.
  • on Windows, fd_set is an array of socket handles. Capacity indicates the actual number of sockets that can be stored in the set.

this(uint max);
Set the capacity of this SocketSet. The exact meaning of the max parameter varies from platform to platform.

Throws:
SocketParameterException if max exceeds this platform's maximum socket set size.

this();
Uses the default capacity for the system.

void reset();
Reset the SocketSet so that there are 0 Sockets in the collection.

void add(Socket s);
Add a Socket to the collection.

Throws:
SocketParameterException if the capacity of this SocketSet has been exceeded.

void remove(Socket s);
Remove this Socket from the collection.

const int isSet(Socket s);
Returns nonzero if this Socket is in the collection.

const @property uint max();
Return the capacity of this SocketSet. The exact meaning of the return value varies from platform to platform.

enum SocketOptionLevel: int;
The level at which a socket option is defined:

SOCKET
Socket level

IP
Internet Protocol version 4 level

ICMP
Internet Control Message Protocol level

IGMP
Internet Group Management Protocol level

GGP
Gateway to Gateway Protocol level

TCP
Transmission Control Protocol level

PUP
PARC Universal Packet Protocol level

UDP
User Datagram Protocol level

IDP
Xerox NS protocol level

RAW
Raw IP packet level

IPV6
Internet Protocol version 6 level

struct Linger;
Linger information for use with SocketOption.LINGER.

l_onoff_t on;
Nonzero for on.

l_linger_t time;
Linger time.

enum SocketOption: int;
Specifies a socket option:

DEBUG
Record debugging information

BROADCAST
Allow transmission of broadcast messages

REUSEADDR
Allow local reuse of address

LINGER
Linger on close if unsent data is present

OOBINLINE
Receive out-of-band data in band

SNDBUF
Send buffer size

RCVBUF
Receive buffer size

DONTROUTE
Do not route

SNDTIMEO
Send timeout

RCVTIMEO
Receive timeout

ERROR
Retrieve and clear error status

KEEPALIVE
Enable keep-alive packets

ACCEPTCONN
Listen

RCVLOWAT
Minimum number of input bytes to process

SNDLOWAT
Minimum number of output bytes to process

TYPE
Socket type

TCP_NODELAY
Disable the Nagle algorithm for send coalescing

IPV6_UNICAST_HOPS
IP unicast hop limit

IPV6_MULTICAST_IF
IP multicast interface

IPV6_MULTICAST_LOOP
IP multicast loopback

IPV6_MULTICAST_HOPS
IP multicast hops

IPV6_JOIN_GROUP
Add an IP group membership

IPV6_LEAVE_GROUP
Drop an IP group membership

IPV6_V6ONLY
Treat wildcard bind as AF_INET6-only

class Socket;
Socket is a class that creates a network communication endpoint using the Berkeley sockets interface.

this(AddressFamily af, SocketType type, ProtocolType protocol);
this(AddressFamily af, SocketType type);
this(AddressFamily af, SocketType type, in char[] protocolName);
Create a blocking socket. If a single protocol type exists to support this socket type within the address family, the ProtocolType may be omitted.

this(in AddressInfo info);
Create a blocking socket using the parameters from the specified AddressInfo structure.

this(socket_t sock, AddressFamily af);
Use an existing socket handle.

const @property socket_t handle();
Get underlying socket handle.

const @property bool blocking();
@property void blocking(bool byes);
Get/set socket's blocking flag.

When a socket is blocking, calls to receive(), accept(), and send() will block and wait for data/action. A non-blocking socket will immediately return instead of blocking.

@property AddressFamily addressFamily();
Get the socket's address family.

const @property bool isAlive();
Property that indicates if this is a valid, alive socket.

void bind(Address addr);
Associate a local address with this socket.

void connect(Address to);
Establish a connection. If the socket is blocking, connect waits for the connection to be made. If the socket is nonblocking, connect returns immediately and the connection attempt is still in progress.

void listen(int backlog);
Listen for an incoming connection. bind must be called before you can listen. The backlog is a request of how many pending incoming connections are queued until accepted.

protected Socket accepting();
Called by accept when a new Socket must be created for a new connection. To use a derived class, override this method and return an instance of your class. The returned Socket's handle must not be set; Socket has a protected constructor this() to use in this situation.

Socket accept();
Accept an incoming connection. If the socket is blocking, accept waits for a connection request. Throws SocketAcceptException if unable to accept. See accepting for use with derived classes.

void shutdown(SocketShutdown how);
Disables sends and/or receives.

void close();
Immediately drop any connections and release socket resources. Calling shutdown before close is recommended for connection-oriented sockets. The Socket object is no longer usable after close.

static @property string hostName();
Returns the local machine's host name.

@property Address remoteAddress();
Remote endpoint Address.

@property Address localAddress();
Local endpoint Address.

int ERROR;
Send or receive error code. See wouldHaveBlocked, lastSocketError and Socket.getErrorText for obtaining more information about the error.

ptrdiff_t send(const(void)[] buf, SocketFlags flags);
ptrdiff_t send(const(void)[] buf);
Send data on the connection. If the socket is blocking and there is no buffer space left, send waits.

Returns:
The number of bytes actually sent, or Socket.ERROR on failure.

ptrdiff_t sendTo(const(void)[] buf, SocketFlags flags, Address to);
ptrdiff_t sendTo(const(void)[] buf, Address to);
ptrdiff_t sendTo(const(void)[] buf, SocketFlags flags);
ptrdiff_t sendTo(const(void)[] buf);
Send data to a specific destination Address. If the destination address is not specified, a connection must have been made and that address is used. If the socket is blocking and there is no buffer space left, sendTo waits.

Returns:
The number of bytes actually sent, or Socket.ERROR on failure.

ptrdiff_t receive(void[] buf, SocketFlags flags);
ptrdiff_t receive(void[] buf);
Receive data on the connection. If the socket is blocking, receive waits until there is data to be received.

Returns:
The number of bytes actually received, 0 if the remote side has closed the connection, or Socket.ERROR on failure.

ptrdiff_t receiveFrom(void[] buf, SocketFlags flags, ref Address from);
ptrdiff_t receiveFrom(void[] buf, ref Address from);
ptrdiff_t receiveFrom(void[] buf, SocketFlags flags);
ptrdiff_t receiveFrom(void[] buf);
Receive data and get the remote endpoint Address. If the socket is blocking, receiveFrom waits until there is data to be received.

Returns:
The number of bytes actually received, 0 if the remote side has closed the connection, or Socket.ERROR on failure.

int getOption(SocketOptionLevel level, SocketOption option, void[] result);
Get a socket option.

Returns:
The number of bytes written to result.

int getOption(SocketOptionLevel level, SocketOption option, out int32_t result);
Common case of getting integer and boolean options.

int getOption(SocketOptionLevel level, SocketOption option, out Linger result);
Get the linger option.

void getOption(SocketOptionLevel level, SocketOption option, out Duration result);
Get a timeout (duration) option.

void setOption(SocketOptionLevel level, SocketOption option, int32_t value);
Common case for setting integer and boolean options.

void setOption(SocketOptionLevel level, SocketOption option, Linger value);
Set the linger option.

void setOption(SocketOptionLevel level, SocketOption option, Duration value);
Sets a timeout (duration) option, i.e. SocketOption.SNDTIMEO or RCVTIMEO. Zero indicates no timeout.

In a typical application, you might also want to consider using a non-blocking socket instead of setting a timeout on a blocking one.

Note:
While the receive timeout setting is generally quite accurate on *nix systems even for smaller durations, there are two issues to be aware of on Windows: First, although undocumented, the effective timeout duration seems to be the one set on the socket plus half a second. setOption() tries to compensate for that, but still, timeouts under 500ms are not possible on Windows. Second, be aware that the actual amount of time spent until a blocking call returns randomly varies on the order of 10ms.

Parameters:
SocketOptionLevel level The level at which a socket option is defined.
SocketOption option Either SocketOption.SNDTIMEO or SocketOption.RCVTIMEO.
Duration value The timeout duration to set. Must not be negative.

Throws:
SocketException if setting the options fails.

Example:
import std.datetime;
auto pair = socketPair();
scope(exit) foreach (s; pair) s.close();

// Set a receive timeout, and then wait at one end of
// the socket pair, knowing that no data will arrive.
pair[0].setOption(SocketOptionLevel.SOCKET,
    SocketOption.RCVTIMEO, dur!"seconds"(1));

auto sw = StopWatch(AutoStart.yes);
ubyte[1] buffer;
pair[0].receive(buffer);
writefln("Waited %s ms until the socket timed out.",
    sw.peek.msecs);

string getErrorText();
Get a text description of this socket's error status, and clear the socket's error status.

void setKeepAlive(int time, int interval);
Enables TCP keep-alive with the specified parameters.

Parameters:
int time Number of seconds with no activity until the first keep-alive packet is sent.
int interval Number of seconds between when successive keep-alive packets are sent if no acknowledgement is received.

Throws:
SocketOSException if setting the options fails, or SocketFeatureException if setting keep-alive parameters is unsupported on the current platform.

static int select(SocketSet checkRead, SocketSet checkWrite, SocketSet checkError, Duration timeout);
static int select(SocketSet checkRead, SocketSet checkWrite, SocketSet checkError);
static int select(SocketSet checkRead, SocketSet checkWrite, SocketSet checkError, TimeVal* timeout);
Wait for a socket to change status. A wait timeout of or TimeVal, may be specified; if a timeout is not specified or the TimeVal is null, the maximum timeout is used. The TimeVal timeout has an unspecified value when select returns.

Returns:
The number of sockets with status changes, 0 on timeout, or -1 on interruption. If the return value is greater than 0, the SocketSets are updated to only contain the sockets having status changes. For a connecting socket, a write status change means the connection is established and it's able to send. For a listening socket, a read status change means there is an incoming connection request and it's able to accept.

protected Address createAddress();
Returns a new Address object for the current address family. Can be overridden to support other addresses.

class TcpSocket: std.socket.Socket;
TcpSocket is a shortcut class for a TCP Socket.

this(AddressFamily family);
Constructs a blocking TCP Socket.

this();
Constructs a blocking IPv4 TCP Socket.

this(Address connectTo);
Constructs a blocking TCP Socket and connects to an Address.

class UdpSocket: std.socket.Socket;
UdpSocket is a shortcut class for a UDP Socket.

this(AddressFamily family);
Constructs a blocking UDP Socket.

this();
Constructs a blocking IPv4 UDP Socket.

Socket[2] socketPair();
Creates a pair of connected sockets.

The two sockets are indistinguishable.

Throws:
SocketException if creation of the sockets fails.

Example:
immutable ubyte[] data = [1, 2, 3, 4];
auto pair = socketPair();
scope(exit) foreach (s; pair) s.close();

pair[0].send(data);

auto buf = new ubyte[data.length];
pair[1].receive(buf);
assert(buf == data);