Re: [libmicrohttpd] Clarification on receiving on one thread, replying on another

[Tom Cornell]

On Tue, Oct 25, 2016 at 04:11:12PM +0200, Christian Grothoff wrote:
> On 10/25/2016 03:59 PM, Tom Cornell wrote:
> > I will rework the code along the lines you suggest. Thanks for the 
> > quick reply!
> 
> Ok, if it still doesn't work, I suggest you come back with a minimal
> example for us to look at -- easier to discuss with concrete code.

It is working fine now. Thanks again!

Basically, to sum up what I now think I understand,
you can be in any of 4 or 5 states when the access handler 
callback is called:

1. New connection (*con_cls is null)
2. Receiving data (*con_cls is not null, *upload_data_size > 0)
3. Received all data (*con_cls is not null, *upload_data_size is 0)
Aaaaand the ones I was missing:
4. Waiting for response (*con_cls is not null, *upload_data_size is still 0, 
   and the part of *con_cls that holds your response is not filled in)
5. Response ready (*con_cls now holds a response)

If you suspend your connection before returning in state 3, 
and resume it only once the response is in place,
then you will never see state 4.

And of course you only see states 4 and 5 if you return from state 3
without having queued a response already.

Is that more or less correct?

By the way, I've been using MHD for several years now and have been
really happy with it. In this world of interacting networked services, 
MHD has become one of the tools I use most. So thank you for all 
the work you have put into it! It shows.