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wxSocketBase

Derived from

wxEvtHandler

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 Some data has arrived to the socket.
wxSOCKET_OUTPUT The socket is ready to be written to.
wxSOCKET_CONNECTION Incoming connection arrival (server), or connection establishment (client).
wxSOCKET_LOST The connection has been closed.
wxSOCKET_MAX_EVENT This should never happen but the compiler may complain about it.
A brief note on how to use these events:

The wxSOCKET_INPUT event will be issued when the incoming queue was empty and new data arrives, but NOT if new data arrives when there was data waiting in the incoming queue.

The wxSOCKET_OUTPUT event is issued when a socket is first connected with Connect or accepted with Accept, and then, only after an output operation fails because the output buffer was full, and buffer space becomes available again.

The wxSOCKET_CONNECTION event is issued when a connection request completes (client) or when a new connection arrives at the pending connections 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.

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

Members

wxSocketBase::wxSocketBase
wxSocketBase::~wxSocketBase
wxSocketBase::SetFlags
wxSocketBase::SetNotify
wxSocketBase::SetTimeout
wxSocketBase::Notify
wxSocketBase::Ok
wxSocketBase::Error
wxSocketBase::IsConnected
wxSocketBase::IsData
wxSocketBase::IsDisconnected
wxSocketBase::IsNoWait
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::wxSocketBase

wxSocketBase()

Default constructor. Don't use it; use wxSocketClient or wxSocketServer.


wxSocketBase::~wxSocketBase

~wxSocketBase()

Destroys the wxSocketBase object.


wxSocketBase::SetFlags

void SetFlags(wxSocketBase::wxSockFlags flags)

wxSOCKET_NONE Normal functionnality.
wxSOCKET_NOWAIT Get the available data in the input queue and return immediately.
wxSOCKET_WAITALL Wait for all required data unless an error occurs.
wxSOCKET_BLOCK Block the GUI (do not wxYield) 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 controls whether the GUI blocks during IO operations. If this flag is not used, then the application must take extra care to avoid unwanted reentrance.

So:

wxSOCKET_NONE will try to read 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 control whether the GUI blocks.


wxSocketBase::SetNotify

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);
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.


wxSocketBase::SetTimeout

wxsocketbasesettimeout

void SetTimeout(int seconds)

This function sets the default socket timeout in seconds. This timeout applies to IO calls and also to Wait functions if you don't specify a wait interval. If you never use SetTimeout, the default timeout will be 10 minutes.


wxSocketBase::Notify

void Notify(bool notify)

Notify will enable (notify is TRUE) or disable (notify is FALSE) the propagation of socket events.


wxSocketBase::Ok

bool Ok() const

Returns TRUE if the socket is initialized and ready and FALSE in other cases.


wxSocketBase::Error

bool Error() const

Returns TRUE if an error occured in the last IO operation.

The following operations update the Error() status: Read, Write, ReadMsg, WriteMsg, Peek, Unread, Discard.


wxSocketBase::IsConnected

bool IsConnected() const

Returns TRUE if the socket is connected.


wxSocketBase::IsData

bool IsData() const

Returns TRUE if there is data available to be read.


wxSocketBase::IsDisconnected

bool IsDisconnected() const

Returns TRUE if the socket is disconnected.


wxSocketBase::IsNoWait

bool IsNoWait() const

Returns TRUE if the socket mustn't wait.


wxSocketBase::LastCount

wxUint32 LastCount() const

Returns the number of bytes read or written by the last IO call.

The following operations update the LastCount() value: Read, Write, ReadMsg, WriteMsg, Peek, Unread, Discard.


wxSocketBase::LastError

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 tha LastError value). Use Error, instead of LastError, to determine if the last IO call failed. If Error returns TRUE, use LastError to discover the cause of the error.


wxSocketBase::Peek

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 system socket in-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

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

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

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 can alloc the right size for the buffer. 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

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_SPEED flag. For a detailed explanation, see wxSocketBase::SetFlags.

See also

wxSocketBase::Error, wxSocketBase::LastError, wxSocketBase::LastCount, wxSocketBase::SetFlags, wxSocketBase::WriteMsg


wxSocketBase::Unread

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

wxSocketBase& Discard()

This function simply deletes all bytes in the incoming queue. This function doesn't wait. That is, it will behave as if the wxSOCKET_NOWAIT flag was set. The wxSOCKET_SPEED and wxSOCKET_WAITALL flags have no effect on this function.

Use LastCount to see the number of bytes discarded.

If you use Error, it will always return FALSE.


wxSocketBase::Wait

bool Wait(long seconds = -1, long millisecond = 0)

This function waits until one of the following conditions is true: there is data available for reading; the output buffer is empty (you can send new data); the connection has been lost; an incoming connection arrived (only for servers); a connection request has completed (only for clients).

Parameters

seconds

millisecond

Return value

Returns TRUE if an event occured, FALSE if the timeout was reached.

See also

wxSocketBase::WaitForRead, wxSocketBase::WaitForWrite, wxSocketBase::WaitForLost


wxSocketBase::WaitForRead

bool WaitForRead(long seconds = -1, long millisecond = 0)

This function waits until there is data available to be read.

Parameters

seconds

millisecond

Return value

Returns TRUE if there is data to be read, FALSE if the timeout was reached.

See also

wxSocketBase::Wait, wxSocketBase::WaitForWrite, wxSocketBase::WaitForLost


wxSocketBase::WaitForWrite

bool WaitForWrite(long seconds = -1, long millisecond = 0)

This function waits until you can write to the socket.

Parameters

seconds

millisecond

Return value

Returns TRUE if you can write to the socket, FALSE if the timeout was reached.

See also

wxSocketBase::Wait, wxSocketBase::WaitForRead, wxSocketBase::WaitForLost


wxSocketBase::WaitForLost

bool Wait(long seconds = -1, long millisecond = 0)

This function waits until the connection is lost. This may happen if the peer 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


wxSocketBase::RestoreState

void RestoreState()

This function restores the previous state of the socket, as saved with SaveState.

Calls to SaveState / RestoreState can be nested.

See also

wxSocketBase::SaveState


wxSocketBase::SaveState

void SaveState()

This function saves the current state of the socket object in a stack: actually it saves all flags (those set with SetFlags, SetNotify, Notfy) and the state of the asynchronous callbacks (Callback, CallbackData).

Calls to SaveState / RestoreState can be nested.

See also

wxSocketBase::RestoreState


wxSocketBase::GetLocal

wxsocketbasegetlocal

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.


wxSocketBase::GetPeer

wxsocketbasegetlocal

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.


wxSocketBase::SetEventHandler

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 C callback to be called when an event occurs. See Callback and CallbackData.

Parameters

evt_hdlr

id

See also

wxSocketBase::SetNotify, wxSocketBase::Notify, wxSocketEvent, wxEvtHandler, wxSocketBase::Callback, wxSocketBase::CallbackData


wxSocketBase::Callback

wxSocketBase::wxSockCbk Callback(wxSocketBase::wxSockCbk callback)

You can setup a C callback to be called when an event occurs. The callback 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.

Return value

A pointer to the previous callback.

See also

wxSocketBase::CallbackData, wxSocketBase::SetNotify, wxSocketBase::Notify


wxSocketBase::CallbackData

char * CallbackData(char *cdata)

This function sets the the user data which will be passed to a C callback.

Return value

A pointer to the previous user data.

wxSocketBase::Callback, wxSocketBase::SetNotify, wxSocketBase::Notify