[Qt-interest] QUdpSocket issue

[Davide]

I found out that Windows by default limits the socket buffer size.

Here's the solution:

#include "winsock2.h"
#include <windows.h>

int v = -1;
if (::setsockopt(MyQUdpSocket->socketDescriptor(), SOL_SOCKET,
                    SO_RCVBUF, (char *)&v, sizeof(v)) == -1) {
       return 0;  // error!
}

v is the buffer size in bytes (-1 is unlimited).

Hope this helps.

Cheers
Davide

On Thu, Jan 21, 2010 at 19:22, Thiago Macieira <thiago at kde.org> wrote:
> Em Quinta-feira 21 Janeiro 2010, às 12:26:34, Davide escreveu:
>> I don't know exactly how the UDP stack works in windows but I think
>> that there is somewhere a FIFO where the OS (or the Qt framework)
>> stores all the incoming packets that are waiting to be processed. My
>> idea, based on what happen to my application, is that this FIFO has a
>> limited size and lose the old packets if my application isn't fast
>> enough (e.g. when my pc is executing other applications).
>
> Qt's buffers are unlimited in size. So if Qt gets the packet, it won't discard
> it.
>
> However, QUdpSocket is unbuffered. You're talking directly to the OS buffer.
> --
> Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
>  Senior Product Manager - Nokia, Qt Development Frameworks
>      PGP/GPG: 0x6EF45358; fingerprint:
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>
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-- 
Davide Ghezzi