class TSocket: public TNamed

 Create a socket. Connect to the named service at address addr.
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Returns when connection has been accepted by remote side. Use IsValid()
 to check the validity of the socket. Every socket is added to the TROOT
 sockets list which will make sure that any open sockets are properly
 closed on program termination.

 Create a socket. Connect to the specified port # at address addr.
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Returns when connection has been accepted by remote side. Use IsValid()
 to check the validity of the socket. Every socket is added to the TROOT
 sockets list which will make sure that any open sockets are properly
 closed on program termination.

 Create a socket. Connect to named service on the remote host.
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Returns when connection has been accepted by remote side. Use IsValid()
 to check the validity of the socket. Every socket is added to the TROOT
 sockets list which will make sure that any open sockets are properly
 closed on program termination.

 Create a socket; see CreateAuthSocket for the form of url.
 Connect to the specified port # on the remote host.
 If user is specified in url, try authentication as user.
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Returns when connection has been accepted by remote side. Use IsValid()
 to check the validity of the socket. Every socket is added to the TROOT
 sockets list which will make sure that any open sockets are properly
 closed on program termination.

 Create a socket in the Unix domain on 'sockpath'.
 Returns when connection has been accepted by the server. Use IsValid()
 to check the validity of the socket. Every socket is added to the TROOT
 sockets list which will make sure that any open sockets are properly
 closed on program termination.

 Create a socket. The socket will adopt previously opened TCP socket with
 descriptor desc.

 Create a socket. The socket will adopt previously opened Unix socket with
 descriptor desc. The sockpath arg is for info purposes only. Use
 this method to adopt e.g. a socket created via socketpair().

 TSocket copy ctor.

 Close the socket. If option is "force", calls shutdown(id,2) to
 shut down the connection. This will close the connection also
 for the parent of this process. Also called via the dtor (without
 option "force", call explicitly Close("force") if this is desired).

 Return internet address of local host to which the socket is bound.
 In case of error TInetAddress::IsValid() returns kFALSE.

 Return the local port # to which the socket is bound.
 In case of error return -1.

 Waits for this socket to change status. If interest=kRead,
 the socket will be watched to see if characters become available for
 reading; if interest=kWrite the socket will be watched to
 see if a write will not block.
 The argument 'timeout' specifies a maximum time to wait in millisec.
 Default no timeout.
 Returns 1 if a change of status of interest has been detected within
 timeout; 0 in case of timeout; < 0 if an error occured.

 Send a single message opcode. Use kind (opcode) to set the
 TMessage "what" field. Returns the number of bytes that were sent
 (always sizeof(Int_t)) and -1 in case of error. In case the kind has
 been or'ed with kMESS_ACK, the call will only return after having
 received an acknowledgement, making the sending process synchronous.

 Send a status and a single message opcode. Use kind (opcode) to set the
 TMessage "what" field. Returns the number of bytes that were sent
 (always 2*sizeof(Int_t)) and -1 in case of error. In case the kind has
 been or'ed with kMESS_ACK, the call will only return after having
 received an acknowledgement, making the sending process synchronous.

 Send a character string buffer. Use kind to set the TMessage "what" field.
 Returns the number of bytes in the string str that were sent and -1 in
 case of error. In case the kind has been or'ed with kMESS_ACK, the call
 will only return after having received an acknowledgement, making the
 sending process synchronous.

 Send a TMessage object. Returns the number of bytes in the TMessage
 that were sent and -1 in case of error. In case the TMessage::What
 has been or'ed with kMESS_ACK, the call will only return after having
 received an acknowledgement, making the sending process synchronous.
 Returns -4 in case of kNoBlock and errno == EWOULDBLOCK.
 Returns -5 if pipe broken or reset by peer (EPIPE || ECONNRESET).
 support for streaming TStreamerInfo added by Rene Brun May 2008
 support for streaming TProcessID added by Rene Brun June 2008

 Send an object. Returns the number of bytes sent and -1 in case of error.
 In case the "kind" has been or'ed with kMESS_ACK, the call will only
 return after having received an acknowledgement, making the sending
 synchronous.

 Send a raw buffer of specified length. Using option kOob one can send
 OOB data. Returns the number of bytes sent or -1 in case of error.
 Returns -4 in case of kNoBlock and errno == EWOULDBLOCK.
 Returns -5 if pipe broken or reset by peer (EPIPE || ECONNRESET).

 Check if TStreamerInfo must be sent. The list of TStreamerInfo of classes
 in the object in the message is in the fInfos list of the message.
 We send only the TStreamerInfos not yet sent on this socket.

 Check if TProcessIDs must be sent. The list of TProcessIDs
 in the object in the message is found by looking in the TMessage bits.
 We send only the TProcessIDs not yet send on this socket.

 Receive a character string message of maximum max length. The expected
 message must be of type kMESS_STRING. Returns length of received string
 (can be 0 if otherside of connection is closed) or -1 in case of error
 or -4 in case a non-blocking socket would block (i.e. there is nothing
 to be read).

 Receive a character string message of maximum max length. Returns in
 kind the message type. Returns length of received string+4 (can be 0 if
 other side of connection is closed) or -1 in case of error or -4 in
 case a non-blocking socket would block (i.e. there is nothing to be read).

 Receives a status and a message type. Returns length of received
 integers, 2*sizeof(Int_t) (can be 0 if other side of connection
 is closed) or -1 in case of error or -4 in case a non-blocking
 socket would block (i.e. there is nothing to be read).

 Receive a TMessage object. The user must delete the TMessage object.
 Returns length of message in bytes (can be 0 if other side of connection
 is closed) or -1 in case of error or -4 in case a non-blocking socket
 would block (i.e. there is nothing to be read) or -5 if pipe broken
 or reset by peer (EPIPE || ECONNRESET). In those case mess == 0.

 Receive a raw buffer of specified length bytes. Using option kPeek
 one can peek at incoming data. Returns number of received bytes.
 Returns -1 in case of error. In case of opt == kOob: -2 means
 EWOULDBLOCK and -3 EINVAL. In case of non-blocking mode (kNoBlock)
 -4 means EWOULDBLOCK. Returns -5 if pipe broken or reset by
 peer (EPIPE || ECONNRESET).

 Receive a message containing streamer infos. In case the message contains
 streamer infos they are imported, the message will be deleted and the
 method returns kTRUE.

 Receive a message containing process ids. In case the message contains
 process ids they are imported, the message will be deleted and the
 method returns kTRUE.

 Set socket options.

 Get socket options. Returns -1 in case of error.

 Returns error code. Meaning depends on context where it is called.
 If no error condition returns 0 else a value < 0.
 For example see TServerSocket ctor.

 See comments for function SetCompressionSettings

 See comments for function SetCompressionSettings

 Used to specify the compression level and algorithm:
  settings = 100 * algorithm + level

  level = 0, objects written to this file will not be compressed.
  level = 1, minimal compression level but fast.

  level = 9, maximal compression level but slower and might use more memory.
 (For the currently supported algorithms, the maximum level is 9)
 If compress is negative it indicates the compression level is not set yet.

 The enumeration ROOT::ECompressionAlgorithm associates each
 algorithm with a number. There is a utility function to help
 to set the value of the argument. For example,
   ROOT::CompressionSettings(ROOT::kLZMA, 1)
 will build an integer which will set the compression to use
 the LZMA algorithm and compression level 1.  These are defined
 in the header file Compression.h.

 Note that the compression settings may be changed at any time.
 The new compression settings will only apply to branches created
 or attached after the setting is changed and other objects written
 after the setting is changed.

 Authenticated the socket with specified user.

 Creates a socket or a parallel socket and authenticates to the
 remote server.

 url: [[proto][p][auth]://][user@]host[:port][/service][?options]

 where  proto = "sockd", "rootd", "proofd"
                indicates the type of remote server;
                if missing "sockd" is assumed ("sockd" indicates
                any remote server session using TServerSocket)
          [p] = for parallel sockets (forced internally for
                rootd; ignored for proofd)
       [auth] = "up", "s", "k", "g", "h", "ug" to force UsrPwd,
                SRP, Krb5, Globus, SSH or UidGid authentication
       [port] = is the remote port number
    [service] = service name used to determine the port
                (for backward compatibility, specification of
                 port as priority)
     options  = "m" or "s", when proto=proofd indicates whether
                we are master or slave (used internally by
                TSlave)

 An already opened connection can be used by passing its socket
 in opensock.

 If 'err' is defined, '*err' on return from a failed call contains an error
 code (see NetErrors.h).

 Example:

   TSocket::CreateAuthSocket("rootds://qwerty@machine.fq.dn:5051")

   creates an authenticated socket to a rootd server running
   on remote machine machine.fq.dn on port 5051; "parallel" sockets
   are forced internally because rootd expects
   parallel sockets; however a simple socket will be created
   in this case because the size is 0 (the default);
   authentication will attempt protocol SRP first.

   TSocket::CreateAuthSocket("pk://qwerty@machine.fq.dn:5052",3)

   creates an authenticated parallel socket of size 3 to a sockd
   server running on remote machine machine.fq.dn on port 5052;
   authentication will attempt protocol Kerberos first.

 NB: may hang if the remote server is not of the correct type;
     at present TSocket has no way to find out the type of the
     remote server automatically

 Returns pointer to an authenticated socket or 0 if creation or
 authentication is unsuccessful.

 Creates a socket or a parallel socket and authenticates to the
 remote server specified in 'url' on remote 'port' as 'user'.

 url: [[proto][p][auth]://]host[/?options]

 where  proto = "sockd", "rootd", "proofd"
                indicates the type of remote server
                if missing "sockd" is assumed ("sockd" indicates
                any remote server session using TServerSocket)
          [p] = for parallel sockets (forced internally for
                rootd)
       [auth] = "up", "s", "k", "g", "h", "ug" to force UsrPwd,
                SRP, Krb5, Globus, SSH or UidGid authentication
    [options] = "m" or "s", when proto=proofd indicates whether
                we are master or slave (used internally by TSlave)

 An already opened connection can be used by passing its socket
 in opensock.

 If 'err' is defined, '*err' on return from a failed call contains an error
 code (see NetErrors.h).

 Example:

   TSocket::CreateAuthSocket("qwerty","rootdps://machine.fq.dn",5051)

   creates an authenticated socket to a rootd server running
   on remote machine machine.fq.dn on port 5051; "parallel"
   sockets are forced internally because rootd expects
   parallel sockets; however a simple socket will be created
   in this case because the size is 0 (the default);
   authentication will attempt protocol SRP first.

   TSocket::CreateAuthSocket("qwerty","pk://machine.fq.dn:5052",3)

   creates an authenticated parallel socket of size 3 to a sockd
   server running on remote machine machine.fq.dn on port 5052;
   authentication will attempt protocol Kerberos first.

 NB: may hang if the remote server is not of the correct type;
     at present TSocket has no way to find out the type of the
     remote server automatically

 Returns pointer to an authenticated socket or 0 if creation or
 authentication is unsuccessful.

 Static method returning supported client protocol.

 Print error string depending on error code.

 Get total number of bytes sent via all sockets.

 Get total number of bytes received via all sockets.