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From: Larry on 29 Jan 2010 08:53
"Mihajlo Cvetanović" <mcvetanovic(a)gmail> ha scritto nel messaggio
news:eNHKJFNoKHA.5344(a)TK2MSFTNGP04.phx.gbl...

> Actually "next time" has just come. When Consumer leaves its main loop it
> erases the element from eventi map and then also from users map. But in
> between the Producer may just find this element in its loop, feed some
> data into users map, and call SetEvent with non-existing element! SetEvent
> may or may not crash, I don't know and would dare not to test it in
> working environment.

Ok! what about this?

while(1)
{
// CALLBACK EVENT
WaitForSingleObject(hevent, INFINITE);

EnterCriticalSection(&users_mutex);
int flag = users[threadid].cb.at(0).flag;
string line = (char*)users[threadid].cb.at(0).data;
ResetEvent(hevent);
LeaveCriticalSection(&users_mutex);

if(flag == BUFF_DONE)
{
int ret = s->SendBytes(line + CRLF);
if(SOCKET_ERROR == ret)
break;
}
}

// Close && Remove "event" and "users" from their maps
//
EnterCriticalSection(&users_mutex);
users.erase(threadid);
LeaveCriticalSection(&users_mutex);

EnterCriticalSection(&eventi_mutex);
eventi.erase(threadid);
LeaveCriticalSection(&eventi_mutex);
CloseHandle(hevent);

> And one more problem connected with previous one, a race condition:
> Producer may produce faster than Consumer can consume (even with
> Sleep(1000) you are not really safe). The effect: some data is not sent,
> because the Consumer sends only lastly produced data. The fix: in Consumer
> erase all consumed data, and consume from the end instead from beginning,
> and don't ResetEvent if there are more data to consume.

Well, since I am using pushing back in the circula buffer what I push is the
newest data and so forth. On the Consumer I need to get oldest data...or
maybe I ma getting that wrong...

From: Mihajlo Cvetanović on 29 Jan 2010 10:00
Larry wrote:
> Ok! what about this?

Good :-)

> Well, since I am using pushing back in the circula buffer what I push is
> the newest data and so forth. On the Consumer I need to get oldest
> data...or maybe I ma getting that wrong...

When Consumer gets the oldest data (cb[0]) it goes for another spin, and
what it gets then? Same thing: cb[0]. Is this what you intended? Maybe
you want to discard oldest data after you consume it?
From: Larry on 29 Jan 2010 11:06
"Mihajlo Cvetanović" <mcvetanovic(a)gmail> ha scritto nel messaggio
news:O5yaAPPoKHA.5776(a)TK2MSFTNGP04.phx.gbl...

> When Consumer gets the oldest data (cb[0]) it goes for another spin, and
> what it gets then? Same thing: cb[0]. Is this what you intended? Maybe you
> want to discard oldest data after you consume it?

well, consider this:

cb->push_back(); 1
cb->push_back(); 2
cb->push_back(); 3
cb->push_back(); 4

old->new 1,2,3,4

so I will need in order 1,2,3,4

1 is at index 0, then 2 will be at index 0 etc...

that's my view.

Also, I should consider calling pop_front() after reding from it (front is
index 0)

From: Larry on 30 Jan 2010 15:41
"Larry" <dontmewithme(a)got.it> ha scritto nel messaggio
news:4b6307a3$0$825$4fafbaef(a)reader5.news.tin.it...

>> When Consumer gets the oldest data (cb[0]) it goes for another spin, and
>> what it gets then? Same thing: cb[0]. Is this what you intended? Maybe
>> you want to discard oldest data after you consume it?

by the way, I was thinking about different approach what about the
follwoing?

circular_buffer<buffer> cb_local(numbuff);

while(1)
{
WaitForSingleObject(hevent, INFINITE);

EnterCriticalSection(&users_mutex);
cb_local.swap(users[threadid]);
LeaveCriticalSection(&users_mutex);

while (!cb_local.empty())
{
int ret = s->SendBytes(cb_local.at(0).data);
if (SOCKET_ERROR == ret)
return ret;
cb_local.pop_front();
}
}

thanks

From: Ulrich Eckhardt on 1 Feb 2010 03:28
Larry wrote:
> by the way, I was thinking about different approach what about the
> follwoing?
>
> circular_buffer<buffer> cb_local(numbuff);
>
> while(1)
> {
> WaitForSingleObject(hevent, INFINITE);
>
> EnterCriticalSection(&users_mutex);
> cb_local.swap(users[threadid]);
> LeaveCriticalSection(&users_mutex);
>
> while (!cb_local.empty())
> {
> int ret = s->SendBytes(cb_local.at(0).data);
> if (SOCKET_ERROR == ret)
> return ret;
> cb_local.pop_front();
> }
> }

Yep, good approach.

Uli

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