Re: [RFA] exceptions.h: Fix definition of TRY_CATCH

Daniel Jacobowitz
2005-03-09T17:40:20Z

On Wed, Mar 09, 2005 at 05:48:03PM +0100, Corinna Vinschen wrote:
> If you inspect it, you'll see that the first parameter `env' is evaluated
> three times. Since the first parameter is a call to the function
> exceptions_state_mc_init(), the result is that three new catcher structures
> are created. But only one of them, the last one which has been created,
> is correctly iniitialized by the call to exceptions_state_mc_action_iter().
> I guess you see what will happen at one point. A non-initialized catcher
> is current when the function exceptions_state_mc_action_iter_1() is called
> ==> internal_error.
>
> Note that this is *not* a flaw in newlib or Cygwin. It's perfectly fine
> that setjmp and sigsetjmp are defined as macros as above, see
> http://www.opengroup.org/onlinepubs/009695399/functions/setjmp.html and
> http://www.opengroup.org/onlinepubs/009695399/functions/sigsetjmp.html,
> so the usual macro expansion restrictions apply.
>
> Conclusion: The actual problem is that the sigjmp_buf is created in a
> function call which is the first parameter to sigsetjmp.

Nice catch!

> Solution: Don't do it. :-)
>
> A patch is below. Tested on Cygwin and Linux.
>
>
> Ok to check in?
>
>
> Corinna
>
>
> * exceptions.h (TRY_CATCH): Define setjmp/sigsetjmp macro save.

Yes, this is OK (save -> safe in the changelog).

--
Daniel Jacobowitz
CodeSourcery, LLC