On Mon, 25 Feb 2008 16:24:43 +0100, Igor Stasenko wrote:

> I think it was done intentionally,
> when socket closed , it signals that data available, to awake process
> which waiting for data. Then, when process tries to read it, it
> returns 0 bytes.

Nothing speaks against such behavior except the method's comment "Wait for  
the given nr of seconds for data to arrive. Signal a time out or  
connection close exception if either happens before data becomes  
available."

> I think it's same as with socket's read() function.
> If remote side closed gracefully, a blocking read() function returns
> with 0, indicating that there 0 bytes read, and connection is closed.

So senders of #waitForDataFor: cannot know about closed connections (even  
if the comment says the opposite) and *must* do at least #receiveSomeData  
because #waitForDataFor: can't handle all the possible situations?

> On 25/02/2008, Klaus D. Witzel wrote:
>> I'm trying to provoke the Exceptions which Socket>>#waitForDataFor:  
>> would
>>  signal on failure (and test that it does so), to no avail (no, the  
>> .image
>>  isn't locked and the process doesn't hang).
>>
>>  The below runs in both the Squeak 3.9,3.8 final .images with both the
>>  3.10.2,3.10.6 VMs on win32; the worker process always terminates  
>> without
>>  an exception.
>>
>>  The implementation of #waitForDataFor:
>>  (#waitForDataFor:ifClosed:ifTimedOut:) looks like #dataAvailable  
>> returns
>>  true but there cannot be any data since nothing was ever sent. *but*  
>> after
>>  closing the client side, the other side's #dataAvailable
>>  (#primSocketReceiveDataAvailable) returns true ...
>>
>>  Any hint(s) on what's going on (or wrong) will be recognized with
>>  gratitude.
>>
>>  /Klaus
>>
>>   | localhost serverSocket sessionSocket clientSocket worker |
>>
>>   localhost := NetNameResolver localHostAddress.
>>  "warning:" Socket allInstancesDo: [:socket | socket destroy].
>>   serverSocket := Socket newTCP listenOn: 7680 backlogSize: 1.
>>   clientSocket := Socket newTCP connectNonBlockingTo: localhost port:  
>> 7680.
>>   sessionSocket := serverSocket waitForAcceptFor: 1.
>>   worker := [sessionSocket waitForDataFor: 1] fork.
>>   Processor yield.
>>   Transcript cr; show: serverSocket statusString, ' [server]';
>>         cr; show: clientSocket statusString, ' [client]';
>>         cr; show: sessionSocket statusString, ' [session],  
>> dataAvailable: '
>>                 , sessionSocket dataAvailable storeString;
>>         cr; show: 'worker: ', worker browserPrintString.
>>   [clientSocket close] on: Exception do: [:ex|].
>>   Processor yield.
>>   Transcript cr; show: serverSocket statusString, ' [server]';
>>         cr; show: clientSocket statusString, ' [client]';
>>         cr; show: sessionSocket statusString, ' [session],  
>> dataAvailable: '
>>                 , sessionSocket dataAvailable storeString;
>>         cr; show: 'worker: ', worker browserPrintString; cr.
>>   [sessionSocket destroy] on: Exception do: [:ex|].
>>   [clientSocket destroy] on: Exception do: [:ex|].
>>   [serverSocket destroy] on: Exception do: [:ex|]
>>
>>
>>
>
>