Re: [Bug-wget] Remove set_windows_fd_as_blocking_socket()?

[Ray Satiro]

On 8/6/2014 2:47 PM, Gisle Vanem wrote:
> "Ray Satiro" <address@hidden> wrote:
>
> > How many times is select called?
>
> AFAICR that would be 277.000 times too. I.e. only 1 loop through 
> set_windows_fd_as_blocking_socket().

That's fine then.

> > The function should only be called on a non-blocking socket to set it 
> > blocking. It was needed because gnulib's select called 
> > WSAEventSelect() which turns blocking sockets into non-blocking. 
> > After every select call in wget the socket had to be turned back into 
> > blocking because wget used blocking sockets.
>
> True. MSDN [1] has this to say:
>  The WSAEventSelect function automatically sets socket s to 
> nonblocking  mode, regardless of the value of lNetworkEvents. ...
>
> But:
>  To set socket s back to blocking mode, it is first necessary to clear 
> the event  record associated with socket s via a call to 
> WSAEventSelect with lNetworkEvents  set to zero and the hEventObject 
> parameter set to NULL. You can then call  ioctlsocketor WSAIoctl to 
> set the socket back to blocking mode.
>
> I.e.: WSAEventSelect(NULL,0). So I fail to see why the current
> wait-loop with is needed or even better. How can a 'ioctl (fd, 
> FIONBIO, &zero)'
> be in-progress?

Yup, true. I quote that msdn remark in the e-mail I sent to gnulib devs. 
But in these cases the sockets should have already been set with a null 
event object so I omitted it from the function. Otherwise there'd be a 
lot of unnecessary calls to WSAEventSelect(), like in your sample case 
there'd be at least 277,000.

Now as to whether it's fine to omit the 
WSASetLastError()/WSAGetLastError() I would caution you not to do that. 
It is there to catch a corner case. If the ioctl fails and the error 
code is WSAEINPROGRESS the socket was not converted back to blocking. In 
that specific case we can wait and try again and eventually it will take 
our call.

The alternatives are not appealing to me. I'm satisfied this method 
gives wget best mix of reliability and performance, unless you can prove 
otherwise.

Jay