From: "Raf256" <rmaj AT mail DOT pgd DOT pl>
Newsgroups: comp.os.msdos.djgpp
Subject: Timer interrupt ?
Date: Wed, 29 Aug 2001 00:38:30 +0200
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Hi,
I read the FAQ, but I didn't find all answares...
I have following problem - I'm using alarm() and to detect infinite (or to
long) loops, handler of sigalrm makes long jump to special funcion that
informs tahat program probably had hanged.
Q#1 can I make long jump to instruction that was going to execute when
signal was rised ? I can use it to display something like : Program hanged,
[K]ill, [I]gnore  :-)

Q#2 but alarm wan't work in f(;;), AFAIR because this loop doesn't touch any
data... I think taht timer interrupt 1C might help... can somone PLEASE
write litle example (it's 10-15 lines probably)...
Something like :

jmp_buf jjj;  void handler() { longjmp(jjj,1); }
main() {  /* install handler ????? */   alarm(5);
  if (setjmp(handler,1)) return 1;
  f(;;)
}

Q#3 How should I lock memory in this example ? I heard that all data touched
in signal handler should be atomic_t but I need jum_buf...

Q#4 In FAQ it is written that it's impossible to determinate size of C/C++
function ? But Allegro is doing this simply by putting empty function right
after original function and checking it's adress...

Thanx :)