Derived from
Include files
<wx/socket.h>
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 (server), or 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 succesfully (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 delayed connection request fails.
Event handling
To process events from a socket, use the following event handler macro to direct input to member functions that take a wxSocketEvent argument.
EVT_SOCKET(id, func) | A socket event occured. |
See also
wxSocketEvent, wxSocketClient, wxSocketServer, Sockets sample
Members
wxSocketBase::wxSocketBase
wxSocketBase::~wxSocketBase
wxSocketBase::SetFlags
wxSocketBase::SetNotify
wxSocketBase::SetTimeout
wxSocketBase::Notify
wxSocketBase::Ok
wxSocketBase::Error
wxSocketBase::IsConnected
wxSocketBase::IsData
wxSocketBase::IsDisconnected
wxSocketBase::LastCount
wxSocketBase::LastError
wxSocketBase::Peek
wxSocketBase::Read
wxSocketBase::Write
wxSocketBase::WriteMsg
wxSocketBase::ReadMsg
wxSocketBase::Unread
wxSocketBase::Discard
wxSocketBase::Wait
wxSocketBase::WaitForRead
wxSocketBase::WaitForWrite
wxSocketBase::WaitForLost
wxSocketBase::RestoreState
wxSocketBase::SaveState
wxSocketBase::GetLocal
wxSocketBase::GetPeer
wxSocketBase::SetEventHandler
wxSocketBase::Callback
wxSocketBase::CallbackData
wxSocketBase()
Default constructor. Don't use it; use wxSocketClient or wxSocketServer.
~wxSocketBase()
Destructor.
void SetFlags(wxSocketBase::wxSockFlags flags)
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. |
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.
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.
void SetNotify(wxSocketEventFlags flags)
SetNotify specifies which socket events are to be sent to the event handler. The flags parameter is a combination of flags ORed toghether. 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.
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 is set to 10 minutes.
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.
bool Ok() const
Returns TRUE if the socket is initialized and ready and FALSE in other cases.
bool Error() const
Returns TRUE if an error occured in the last IO operation.
Use this function to check for an error condition after one of the following calls: Read, Write, ReadMsg, WriteMsg, Peek, Unread, Discard.
bool IsConnected() const
Returns TRUE if the socket is connected.
bool IsData() const
Returns TRUE if there is data available to be read.
bool IsDisconnected() const
Returns TRUE if the socket is not connected.
wxUint32 LastCount() const
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: Read, Write, ReadMsg, WriteMsg, Peek, Unread, Discard.
wxSocketError LastError() const
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 occured (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.
wxSocketBase& Peek(char * buffer, wxUint32 nbytes)
This function peeks a buffer of nbytes bytes from the socket. Peeking a buffer doesn't delete it from the socket input queue.
Use LastCount to verify the number of bytes actually peeked.
Use Error to determine if the operation succeeded.
Parameters
buffer
nbytes
Return value
Returns a reference to the current object.
Remark/Warning
The exact behaviour of wxSocketBase::Peek() depends on the combination of flags being used. For a detailed explanation, see wxSocketBase::SetFlags
See also
wxSocketBase::Error, wxSocketBase::LastError, wxSocketBase::LastCount, wxSocketBase::SetFlags
wxSocketBase& Read(char * buffer, wxUint32 nbytes)
This function reads a buffer of nbytes bytes from the socket.
Use LastCount to verify the number of bytes actually read.
Use Error to determine if the operation succeeded.
Parameters
buffer
nbytes
Return value
Returns a reference to the current object.
Remark/Warning
The exact behaviour of wxSocketBase::Read() depends on the combination of flags being used. For a detailed explanation, see wxSocketBase::SetFlags.
See also
wxSocketBase::Error, wxSocketBase::LastError, wxSocketBase::LastCount, wxSocketBase::SetFlags
wxSocketBase& Write(const char * buffer, wxUint32 nbytes)
This function writes a buffer of nbytes bytes to the socket.
Use LastCount to verify the number of bytes actually written.
Use Error to determine if the operation succeeded.
Parameters
buffer
nbytes
Return value
Returns a reference to the current object.
Remark/Warning
The exact behaviour of wxSocketBase::Write() depends on the combination of flags being used. For a detailed explanation, see wxSocketBase::SetFlags.
See also
wxSocketBase::Error, wxSocketBase::LastError, wxSocketBase::LastCount, wxSocketBase::SetFlags
wxSocketBase& WriteMsg(const char * buffer, wxUint32 nbytes)
This function writes a buffer of nbytes bytes from the socket, but it writes a short header before so that ReadMsg knows how much data should it actually read. So, a buffer sent with WriteMsg must be read with ReadMsg. This function always waits for the entire buffer to be sent, unless an error occurs.
Use LastCount to verify the number of bytes actually written.
Use Error to determine if the operation succeeded.
Parameters
buffer
nbytes
Return value
Returns a reference to the current object.
Remark/Warning
wxSocketBase::WriteMsg() will behave as if the wxSOCKET_WAITALL flag was always set and it will always ignore the wxSOCKET_NOWAIT flag. The exact behaviour of WriteMsg depends on the wxSOCKET_BLOCK flag. For a detailed explanation, see wxSocketBase::SetFlags.
See also
wxSocketBase::Error, wxSocketBase::LastError, wxSocketBase::LastCount, wxSocketBase::SetFlags, wxSocketBase::ReadMsg
wxSocketBase& ReadMsg(char * buffer, wxUint32 nbytes)
This function reads a buffer sent by WriteMsg on a socket. If the buffer passed to the function isn't big enough, the remaining bytes will be discarded. This function always waits for the buffer to be entirely filled, unless an error occurs.
Use LastCount to verify the number of bytes actually read.
Use Error to determine if the operation succeeded.
Parameters
buffer
nbytes
Return value
Returns a reference to the current object.
Remark/Warning
wxSocketBase::ReadMsg() will behave as if the wxSOCKET_WAITALL flag was always set and it will always ignore the wxSOCKET_NOWAIT flag. The exact behaviour of ReadMsg depends on the wxSOCKET_BLOCK flag. For a detailed explanation, see wxSocketBase::SetFlags.
See also
wxSocketBase::Error, wxSocketBase::LastError, wxSocketBase::LastCount, wxSocketBase::SetFlags, wxSocketBase::WriteMsg
wxSocketBase& Unread(const char * buffer, wxUint32 nbytes)
This function unreads a buffer. That is, the data in the buffer is put back in the incoming queue. This function is not affected by wxSocket flags.
If you use LastCount, it will always return nbytes.
If you use Error, it will always return FALSE.
Parameters
buffer
nbytes
Return value
Returns a reference to the current object.
See also
wxSocketBase::Error, wxSocketBase::LastCount, wxSocketBase::LastError
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.
bool Wait(long seconds = -1, long millisecond = 0)
This function waits until one of the following conditions is TRUE. Note that it is recommended to use the individual Wait functions to wait for the required condition, instead of this one.
Parameters
seconds
millisecond
Return value
Returns TRUE when any of the above conditions is satisfied, FALSE if the timeout was reached.
See also
wxSocketBase::WaitForRead, wxSocketBase::WaitForWrite, wxSocketBase::WaitForLost
bool WaitForRead(long seconds = -1, long millisecond = 0)
This function waits until there is data available to be read, or until an error occurs.
Parameters
seconds
millisecond
Return value
Returns TRUE if there is data to be read, FALSE if the timeout was reached or an error occured.
See also
wxSocketBase::Wait, wxSocketBase::WaitForWrite, wxSocketBase::WaitForLost
bool WaitForWrite(long seconds = -1, long millisecond = 0)
This function waits until the socket is ready to send data, or until an error occurs.
Parameters
seconds
millisecond
Return value
Returns TRUE if you can write to the socket, FALSE if the timeout was reached or an error occured.
See also
wxSocketBase::Wait, wxSocketBase::WaitForRead, wxSocketBase::WaitForLost
bool Wait(long seconds = -1, long 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.
Parameters
seconds
millisecond
Return value
Returns TRUE if the connection was lost, FALSE if the timeout was reached.
See also
wxSocketBase::WaitForRead, wxSocketBase::WaitForWrite, wxSocketBase::WaitForLost
void RestoreState()
This function restores the previous state of the socket, as saved with SaveState
Calls to SaveState and RestoreState can be nested.
See also
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, and current settings for the asynchronous callbacks, as set with Callback and CallbackData.
Calls to SaveState and RestoreState can be nested.
See also
bool GetLocal(wxSockAddress& addr_man) const
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, ...).
Return value
It returns TRUE if no errors happened, FALSE otherwise.
bool GetPeer(wxSockAddress& addr_man) const
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, ...).
Return value
It returns TRUE if no errors happened, FALSE otherwise.
void SetEventHandler(wxEvtHandler& evt_hdlr, int id = -1)
Sets an event handler to be called when a socket event occurs. The handler will be called for those events for which notification is enabled with SetNotify and Notify.
You can also specify a callback function to be called when an event occurs, although if possible, events should be used instead of callbacks. See Callback and CallbackData.
Parameters
evt_hdlr
id
See also
wxSocketBase::SetNotify, wxSocketBase::Notify, wxSocketEvent, wxEvtHandler, wxSocketBase::Callback, wxSocketBase::CallbackData
wxSocketBase::wxSockCbk Callback(wxSocketBase::wxSockCbk callback)
You can setup a callback function to be called when an event occurs. The function will be called only for those events for which notification has been enabled with Notify and SetNotify. The prototype of the callback must be as follows:
void SocketCallback(wxSocketBase& sock, wxSocketNotify evt, char *cdata);The first parameter is a reference to the socket object in which the event occured. The second parameter tells you which event occured. (See wxSocket events). The third parameter is the user data you specified using CallbackData.
Note that events are preferred over callbacks where possible.
Return value
A pointer to the previous callback.
See also
wxSocketBase::CallbackData, wxSocketBase::SetNotify, wxSocketBase::Notify
char * CallbackData(char *cdata)
This function sets the the user data which will be passed to a callback function set via Callback.
Note that events are preferred over callbacks where possible.
Return value
A pointer to the previous user data.
wxSocketBase::Callback, wxSocketBase::SetNotify, wxSocketBase::Notify