[gambit-list] Interrupted in wait-for-io

Christian christian at pflanze.mine.nu
Wed Jan 4 00:36:17 EST 2006

At 10:18 Uhr -0500 03.01.2006, Marc Feeley wrote:
>CTRL-C does not generate an exception.  It simply calls the current 

Ok, thanks, that makes perfect sense.

Two small followup questions about things I might need in the future:

- can other signals than SIGINT be catched, too? I guess that you 
haven't added that since it's platform specific. I might write a 
small C layer for my programs on unix, but then my question is: how 
do I register an interrupt callback in gambit's runtime (I guess I'll 
have to save the signal number and values into some global and then 
let gambit run a callback synchronously at a safe point)?

- maybe it's rather theoretical, but there is probably a time frame 
between the start of a program and the time when it sets 
user-interrupt-handler where sending SIGINT still makes the program 
"hang" in the debugger. Could gambit delay installing of a SIGINT 
signal handler so that the program behaves in the default way until 
the user actually installs a handler?(*) That should also be better 
if gambit is to be embedded in a C program which wants to catch 
signals itself.

(*) that leads to another question I've been wondering about: 
parameterize doesn't accept procedures which aren't parameters (it 
checks their type). This makes the above suggestion impossible to be 
implement transparently of course, since it would require running 
code other than just for setting the dynamic value (**). What's the 
reason for this restriction?

((**) without this, the user would have to run some 
(user-interrupt-initialize!) hook first -- at least, that might be 
better for thread safety?)


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