.\" This is a wxWidgets manpage page generated from the XML docs .TH wxSocketBase 3wx 2005-02-15 "wxWidgets" "wxWidgets class documentation" .SH NAME wxSocketBase \- Represents a socket base object .SH DESCRIPTION wxSocketBase is the base class for all socket-related objects, and it defines all basic IO functionality. Note: (Workaround for implementation limitation for wxWidgets up to 2.5.x) If you want to use sockets or derived classes such as wxFTP in a secondary thread, call wxSocketBase::Initialize() (undocumented) from the main thread before creating any sockets - in wxApp::OnInit for example. See http://wiki.wxwidgets.org/wiki.pl?WxSocket or http://www.litwindow.com/knowhow/knowhow.html for more details. wxSocket errors wxSOCKET_NOERROR No error happened. wxSOCKET_INVOP Invalid operation. wxSOCKET_IOERR Input/Output error. wxSOCKET_INVADDR Invalid address passed to wxSocket. wxSOCKET_INVSOCK Invalid socket (uninitialized). wxSOCKET_NOHOST No corresponding host. wxSOCKET_INVPORT Invalid port. wxSOCKET_WOULDBLOCK The socket is non-blocking and the operation would block. wxSOCKET_TIMEDOUT The timeout for this operation expired. wxSOCKET_MEMERR Memory exhausted. wxSocket events wxSOCKET_INPUT There is data available for reading. wxSOCKET_OUTPUT The socket is ready to be written to. wxSOCKET_CONNECTION Incoming connection request (server), or successful connection establishment (client). wxSOCKET_LOST The connection has been closed. A brief note on how to use these events: The wxSOCKET_INPUT event will be issued whenever there is data available for reading. This will be the case if the input queue was empty and new data arrives, or if the application has read some data yet there is still more data available. This means that the application does not need to read all available data in response to a wxSOCKET_INPUT event, as more events will be produced as necessary. The wxSOCKET_OUTPUT event is issued when a socket is first connected with Connect or accepted with Accept . After that, new events will be generated only after an output operation fails with wxSOCKET_WOULDBLOCK and buffer space becomes available again. This means that the application should assume that it can write data to the socket until an wxSOCKET_WOULDBLOCK error occurs; after this, whenever the socket becomes writable again the application will be notified with another wxSOCKET_OUTPUT event. The wxSOCKET_CONNECTION event is issued when a delayed connection request completes successfully (client) or when a new connection arrives at the incoming queue (server). The wxSOCKET_LOST event is issued when a close indication is received for the socket. This means that the connection broke down or that it was closed by the peer. Also, this event will be issued if a connection request fails. .SH "PARENTS" wxObject .SH "INCLUDE FILES" wx/socket.h .SH MEMBERS .SS wxSocketBase () Default constructor. Don't use it directly; instead, use wxSocketClient to construct a socket client, or wxSocketServer to construct a socket server. .SS ~wxSocketBase () Destructor. Do not destroy a socket using the delete operator directly; use Destroy instead. Also, do not create socket objects in the stack. .SS void Close () This function shuts down the socket, disabling further transmission and reception of data; it also disables events for the socket and frees the associated system resources. Upon socket destruction, Close is automatically called, so in most cases you won't need to do it yourself, unless you explicitly want to shut down the socket, typically to notify the peer that you are closing the connection. \wxheading{Remark/Warning} Although Close immediately disables events for the socket, it is possible that event messages may be waiting in the application's event queue. The application must therefore be prepared to handle socket event messages even after calling Close. .SS bool Destroy () Destroys the socket safely. Use this function instead of the delete operator, since otherwise socket events could reach the application even after the socket has been destroyed. To prevent this problem, this function appends the wxSocket to a list of object to be deleted on idle time, after all events have been processed. For the same reason, you should avoid creating socket objects in the stack. Destroy calls Close automatically. .SS wxSocketBase& Discard () This function simply deletes all bytes in the incoming queue. This function always returns immediately and its operation is not affected by IO flags. Use LastCount to verify the number of bytes actually discarded. If you use Error , it will always return false. .SS bool Error () Returns true if an error occurred in the last IO operation. Use this function to check for an error condition after one of the following calls: Discard, Peek, Read, ReadMsg, Unread, Write, WriteMsg. .SS void * GetClientData () Returns a pointer of the client data for this socket, as set with SetClientData .SS bool GetLocal (wxSockAddress& addr) This function returns the local address field of the socket. The local address field contains the complete local address of the socket (local address, local port, ...). .SS wxSocketFlags GetFlags () Returns current IO flags, as set with SetFlags .SS bool GetPeer (wxSockAddress& addr) This function returns the peer address field of the socket. The peer address field contains the complete peer host address of the socket (address, port, ...). .SS void InterruptWait () Use this function to interrupt any wait operation currently in progress. Note that this is not intended as a regular way to interrupt a Wait call, but only as an escape mechanism for exceptional situations where it is absolutely necessary to use it, for example to abort an operation due to some exception or abnormal problem. InterruptWait is automatically called when you Close a socket (and thus also upon socket destruction), so you don't need to use it in these cases. wxSocketBase::Wait , wxSocketServer::WaitForAccept , wxSocketBase::WaitForLost , wxSocketBase::WaitForRead , wxSocketBase::WaitForWrite , wxSocketClient::WaitOnConnect .SS bool IsConnected () Returns true if the socket is connected. .SS bool IsData () This function waits until the socket is readable. This might mean that queued data is available for reading or, for streamed sockets, that the connection has been closed, so that a read operation will complete immediately without blocking (unless the wxSOCKET_WAITALL flag is set, in which case the operation might still block). .SS bool IsDisconnected () Returns true if the socket is not connected. .SS wxUint32 LastCount () Returns the number of bytes read or written by the last IO call. Use this function to get the number of bytes actually transferred after using one of the following IO calls: Discard, Peek, Read, ReadMsg, Unread, Write, WriteMsg. .SS wxSocketError LastError () Returns the last wxSocket error. See wxSocket errors . Please note that this function merely returns the last error code, but it should not be used to determine if an error has occurred (this is because successful operations do not change the LastError value). Use Error first, in order to determine if the last IO call failed. If this returns true, use LastError to discover the cause of the error. .SS void Notify (bool notify) According to the notify value, this function enables or disables socket events. If notify is true, the events configured with SetNotify will be sent to the application. If notify is false; no events will be sent. .SS bool Ok () Returns true if the socket is initialized and ready and false in other cases. \wxheading{Remark/Warning} For wxSocketClient , Ok won't return true unless the client is connected to a server. For wxSocketServer , Ok will return true if the server could bind to the specified address and is already listening for new connections. Ok does not check for IO errors; use Error instead for that purpose. .SS void RestoreState () This function restores the previous state of the socket, as saved with SaveState Calls to SaveState and RestoreState can be nested. .SS void SaveState () This function saves the current state of the socket in a stack. Socket state includes flags, as set with SetFlags , event mask, as set with SetNotify and Notify , user data, as set with SetClientData . Calls to SaveState and RestoreState can be nested. .SS void SetClientData (void *data) Sets user-supplied client data for this socket. All socket events will contain a pointer to this data, which can be retrieved with the wxSocketEvent::GetClientData function. .SS void SetEventHandler (wxEvtHandler& handlerint id = -1) .SS void SetFlags (wxSocketFlags flags) Use SetFlags to customize IO operation for this socket. The flags parameter may be a combination of flags ORed together. The following flags can be used: wxSOCKET_NONE Normal functionality. wxSOCKET_NOWAIT Read/write as much data as possible and return immediately. wxSOCKET_WAITALL Wait for all required data to be read/written unless an error occurs. wxSOCKET_BLOCK Block the GUI (do not yield) while reading/writing data. wxSOCKET_REUSEADDR Allows the use of an in-use port (wxServerSocket only) A brief overview on how to use these flags follows. If no flag is specified (this is the same as wxSOCKET_NONE ), IO calls will return after some data has been read or written, even when the transfer might not be complete. This is the same as issuing exactly one blocking low-level call to recv() or send(). Note that blocking here refers to when the function returns, not to whether the GUI blocks during this time. If wxSOCKET_NOWAIT is specified, IO calls will return immediately. Read operations will retrieve only available data. Write operations will write as much data as possible, depending on how much space is available in the output buffer. This is the same as issuing exactly one nonblocking low-level call to recv() or send(). Note that nonblocking here refers to when the function returns, not to whether the GUI blocks during this time. If wxSOCKET_WAITALL is specified, IO calls won't return until ALL the data has been read or written (or until an error occurs), blocking if necessary, and issuing several low level calls if necessary. This is the same as having a loop which makes as many blocking low-level calls to recv() or send() as needed so as to transfer all the data. Note that blocking here refers to when the function returns, not to whether the GUI blocks during this time. The wxSOCKET_BLOCK flag controls whether the GUI blocks during IO operations. If this flag is specified, the socket will not yield during IO calls, so the GUI will remain blocked until the operation completes. If it is not used, then the application must take extra care to avoid unwanted reentrance. The wxSOCKET_REUSEADDR flag controls the use of the SO_REUSEADDR standard setsockopt() flag. This flag allows the socket to bind to a port that is already in use. This is mostly used on UNIX-based systems to allow rapid starting and stopping of a server - otherwise you may have to wait several minutes for the port to become available. This option can have surprising platform dependent behavior, check the documentation for your platform's implementation of setsockopt(). So: wxSOCKET_NONE will try to read at least SOME data, no matter how much. wxSOCKET_NOWAIT will always return immediately, even if it cannot read or write ANY data. wxSOCKET_WAITALL will only return when it has read or written ALL the data. wxSOCKET_BLOCK has nothing to do with the previous flags and it controls whether the GUI blocks. wxSOCKET_REUSEADDR controls special platform-specific behavior for wxServerSocket. .SS void SetNotify (wxSocketEventFlags flags) SetNotify specifies which socket events are to be sent to the event handler. The flags parameter may be combination of flags ORed together. The following flags can be used: wxSOCKET_INPUT_FLAG to receive wxSOCKET_INPUT wxSOCKET_OUTPUT_FLAG to receive wxSOCKET_OUTPUT wxSOCKET_CONNECTION_FLAG to receive wxSOCKET_CONNECTION wxSOCKET_LOST_FLAG to receive wxSOCKET_LOST For example: sock.SetNotify(wxSOCKET_INPUT_FLAG | wxSOCKET_LOST_FLAG); sock.Notify(true); In this example, the user will be notified about incoming socket data and whenever the connection is closed. For more information on socket events see wxSocket events . .SS void SetTimeout (int seconds) This function sets the default socket timeout in seconds. This timeout applies to all IO calls, and also to the Wait family of functions if you don't specify a wait interval. Initially, the default timeout is 10 minutes. .SS wxSocketBase& Peek (void * bufferwxUint32 nbytes) .SS wxSocketBase& Read (void * bufferwxUint32 nbytes) .SS wxSocketBase& ReadMsg (void * bufferwxUint32 nbytes) .SS wxSocketBase& Unread (const void * bufferwxUint32 nbytes) .SS bool Wait (long seconds = -1long millisecond = 0) .SS bool Wait (long seconds = -1long millisecond = 0) This function waits until the connection is lost. This may happen if the peer gracefully closes the connection or if the connection breaks. .SS bool WaitForRead (long seconds = -1long millisecond = 0) .SS bool WaitForWrite (long seconds = -1long millisecond = 0) .SS wxSocketBase& Write (const void * bufferwxUint32 nbytes) .SS wxSocketBase& WriteMsg (const void * bufferwxUint32 nbytes) .SH EVENTS .SS EVT_SOCKET(id, func) Process a wxEVT_SOCKET event. .SH "SEE ALSO" wxObject wxSocketEvent wxSocketClient wxSocketServer Sockets sample .SH "AUTHORS" Documentation content by Julian Smart, Robert Roebling, Vadim Zeitlin, Robin Dunn, et al Conversion to manpage format by Arnout Engelen (http://bzzt.net), bugreports welcome.