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From: jbuck@forney.berkeley.edu (Joe Buck)
Newsgroups: comp.lang.c++
Subject: Re: How do I call destructors on ^C in TC++?
Message-ID: <1991May29.032559.10858@agate.berkeley.edu>
Date: 29 May 91 03:25:59 GMT
References: <1991May24.045847.24401@colorado.edu> <1991May27.024810.2300@minyos.xx.rmit.oz.au> <1991May28.225141.1451@mathcs.sjsu.edu>
Sender: root@agate.berkeley.edu (Charlie Root)
Reply-To: jbuck@forney.berkeley.edu (Joe Buck)
Organization: University of California, Berkeley
Lines: 48

In article <1991May28.225141.1451@mathcs.sjsu.edu>, horstman@mathcs.sjsu.edu (Cay Horstmann) writes:
|> In article <1991May27.024810.2300@minyos.xx.rmit.oz.au> s892992@minyos.xx.rmit.oz.au (Kendall Bennett) writes:
|> >   I am pretty sure that if you call the exit() standard library function it
|> >calls the destructors for any AUTO variables, that is any instances that have
|> >been allocated on the stack. If the class instance was allocted in the heap,
|> >then it is up to the program to delete it - so I don't know how you would
|> >handle this one.
|> >
|> Fat chance. No such thing will happen. When you call exit(), the stack
|> just gets popped, the free store given back wholesale. I am not sure whether
|> STATIC destructors are run. Someone here surely knows the answer. 

Cay's right; there's no provision in Turbo C++ or or cfront up through 2.1
that would allow you to have a control-C interrupt call destructors for
the auto variables.

When exceptions become commonly available, there will be a solution: the
control-C signal handler can throw an exception, and if you want to catch
it at the top level and exit, you can write your main() something like

#include <signal.h>

class IntSignal {
	// stuff goes here
};

void intCatcher() throw IntSignal {
	throw IntSignal();
}

int main (int argc, char ** argv) {
	// I'm being sloppy, should check the current status
	// of signal handling.
	signal (SIGINT, intCatcher);
	try {
		// body of main goes here
	}
	catch (IntSignal& isig) {
		cerr << "Caught a SIGINT, exiting\n";
		exit(1);
	}
}

The exception handling mechanism will cause all auto values on the
stack to have their destructors called.
--
Joe Buck
jbuck@galileo.berkeley.edu	 {uunet,ucbvax}!galileo.berkeley.edu!jbuck