Skip http tests when sigalert == 0

[mgondan]

Is there a way (prologflag?) to test swipl --sigalert=0, so that the http tests can be skipped?

This also relates to
a97b0b1

which added a unit test with a http handler.

[JanWielemaker]

Is there a way (prologflag?) to test swipl --sigalert=0, so that the http tests can be skipped?

What do you want to test for --sigalert=0? Note that this has no impact on Windows as alert signals are not used there. I don't see much reason to test this. It simply means that no signal is send to target thread on thread_signal/2 and thus the receiving thread will not respond as long as it is in a blocking system call. It makes sense to test blocking system calls can be interrupted. That is already in several tests. I don't make much sense to test they cannot be interrupted. Using --sigalert=0 gives you a bit crippled system in non-Windows context. It can be required in some embedding contexts, but should be avoided if possible.

[mgondan]

I am actually struggling with Unix, not windows

[JanWielemaker]

I am actually struggling with Unix, not windows

But the argument why testing makes little sense still holds. What is the problem?

[JanWielemaker]

Ah, I see. The real clue was the title 😄 You can use prolog_alert_signal(0,0) as test that alerting is not supported. Note however that Windows uses another mechanism to signal during blocking system calls (which works for a different set of system calls ...). So, if a test relies on signal handling, you get a condition as below (not tested).

:- if(current_predicate(prolog_alert_signal/2)).
thread_signal_while_in_blocked_call :- 
     prolog_alert_signal(Sig, Sig), Sig \== 0,
     !.
:- endif.
thread_signal_while_in_blocked_call :- 
     current_prolog_flag(windoes, true).

[mgondan]

See PR here
#1469