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When the phone goes out of a coverage area, the data call will drop. When this happens, BREW cleans up the underlying OEM sockets that are in use. The ISocket(s) used by an app continue to exist, and the app will get appropriate error responses when it tries to use them.

For synchronous (TCP/IP) data communication, there are two ways to handle the potentially bad sockets:


Check the return value from all Socket operations

Writing or reading from the socket will cause AEE_NET_ERROR to be returned. In your code, you should check the return value from the Socket connect, read, write and take appropriate action.

// Connect callback
static void SampleApp_ConnectCB(void *cxt, int err) {
SampleApp *pMe = (SampleAppApp*)cxt;

if (err) {
// connect failed
SampleApp_CleanUp(pMe);
//Clean up net manager and
// sockets
ShowMainMenu(pMe);
return;
}

}

// Writing
iRet = ISOCKET_Write(pMe->m_piSock, (byte*)Request,
(uint16)STRLEN(Request));
if (iRet == AEE_NET_ERROR) {
// Write error
SampleApp_CleanUp(pMe);
// Clean up net manager and sockets
ShowMainMenu(pMe);
return;
}


// Reading
iRet = ISOCKET_Read(pMe->m_piSock, (byte*)buf,
sizeof(buf));
if (iRet == AEE_NET_ERROR) {
// Read error
SampleApp_CleanUp(pMe);
// Clean up net manager and sockets
ShowMainMenu(pMe);
return;
}



Register for change in network/socket state

Another way to handle the phone going out of coverage while a data call is in progress is to register for Network and Socket events using INETMGR_OnEvent() and take appropriate action when notified of change in network/socket status. In the example below, a flag is set to indicate that the socket is bad. The socket state is checked before it is used.

For more information on Network and Socket events, please refer to NetMgrEvent and NetState enums in aeenet.h include file.

For example:

// Register to receive Network and Socket events
INETMGR_OnEvent(piNet, (PFNNETMGREVENT)CheckNetStatus,
(void*)pMe, TRUE);

//Callback invoked when Network/Socket event is received
static void CheckNetStatus(void* cxt, NetMgrEvent evt,
uint32, dwData) {
SampleApp *pMe = (SampleApp*)cxt;

if(evt == NE_PPP) {
if(dwData == NET_PPP_CLOSING || dwData ==
NET_PPP_CLOSED) {
// flag set to false to indicate socket is bad
pMe->m_SocketState = FALSE;

// clean up network and socket
ReleaseNetAndSocket(pMe);
}
}

if(evt == NE_SO_CLOSING || evt == NE_SO_CLOSED) {
pMe->m_SocketState = FALSE;
ReleaseNetAndSocket(pMe);
}

if(evt == NE_SO_CONNECTED) {
pMe->m_SocketState = TRUE;
}

return;
}

// Check socket state before using it
static void RoadWarriorApp_ReadCB(void *cxt) {
int rc;
SampleApp *pMe = (SampleApp *)cxt;

if(pMe->m_SocketState == FALSE) { //socket is bad
ReleaseNetAndSocket(pMe);
ShowMainMenu(pMe);
return;
}

rc = ISOCKET_Read(piSock, (byte*)buf, sizeof(buf));

}



When registering for network and socket events using INETMGR_InEvent(), you must de- register before terminating the application by using INETMGR_OnEvent() with bRegister = FALSE.

Note: After the phone goes out of coverage, the sockets are unusable. You must release your ISocket(s) and reinstantiate them when next required. The INetMgr does not need to be released and re-instantiated before using it for the next network operation, however there is no harm in doing so.

To handle potentially bad sockets for asynchronous(UDP) data communication, register for change in network/socket state (described in number 2 above).