improve ONION_ERROR message in onion_response_flush, save errno...

[bstarynk]

This gives a more readable error message. Could be useful for the Bismon static source code analyzer (for C and C++) on https://github.com/bstarynk/bismon/ and perhaps in the RefPerSys symbolic artificial intelligence project on http://refpersys.org/

[davidmoreno]

Why does it need to save and restore errno?

[bstarynk]

On 29/09/2021 15:44, David Moreno Montero wrote:

Why does it need to save and restore errno?

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Because I don't understand the policy regarding errno in libonion.

In my opinion, that policy should be documented (perhaps it is, but I forgot about it).

-- Basile Starynkevitch @.***> (only mine opinions / les opinions sont miennes uniquement) 92340 Bourg-la-Reine, France web page: starynkevitch.net/Basile/

[davidmoreno]

There is no official policy for errno.. but it just does nothing with it.

This way when it returns you have an error reason.

And was thinking of asking to leave it as is and ask for not saving errno... but I do see some value in that the logging does not change errno, so for example if a onion_write fails, and we log it, we still have the errno of the reason for the failure to write into the socket.

So all good!