Re: memory leak in udp roundtrip example?

Hi Charlls,

Charlls Quarra wrote:
> I was trying to find the source of a leak in my asio
> application (nothing outrageously big, but it could
> exhaust 1Gb in a day or so), and i keep reducing the
> code until i reached a minimal skeleton that
> reproduces the leak. I'm not sure if it has been
> reported already since there are no bugs filed in the
> tracker, so i assume it's safe to post it here.

Ok, i'll take a look, however I have spotted a bug in your program :)

The data passed to async_send_to must be valid for the lifetime of the
operation (i.e. until the handler is called), but the string argument
"str" in this function:

> void start_send_to(string& str , udp::endpoint& endp)
> {
>       //strncpy( data_ , str.c_str() , max_length-1 );
>       socket_.async_send_to( asio::buffer( str.c_str() ,
> max_length ) , endp ,
>                                                 
> boost::bind(&server::handle_send_to , this,
>                                                                         
> asio::placeholders::error ,
>                                                                         
> asio::placeholders::bytes_transferred));
> }

Is on the stack at this point in io_main():

>       if ( arg->offset_port != -1 )
>       {
>               // this side will start the echo 
>               udp::resolver::query query(udp::v4(), "0.0.0.0",
> "0");
>               udp::endpoint endp = *resolver.resolve(query);
>               endp.port( arg->port + arg->offset_port );
>               string foo;
>               foo = "foob\n";
>               //foo = "fooBistic";
>               s.start_send_to( *& foo , *& endp );
>               
>       }

and it goes out of scope before the io_service::run(), and so does not
have the correct lifetime.

>     io_service.run();

I'm not sure if this is related to the leak (it probably isn't) but it
should be fixed and the leak test rerun.

Cheers,
Chris

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