c++ char exceptions

c++ char exceptions

[Robert Collins]

I don't know if this is a cygwin issue or if I am doing something
fundamentally wrong...

int
main (int argc, char **argv)
{
  try
    {
      throw "catch this";
    }
  catch (char *message) 
    {
      return 1;
    }
  return 0;
}

coredumps on me. Throwing int's works fine. Throwing (string) "foo"
works fine.

Anyway, this is partly for the archives, partly for curiosity.

Rob

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RE: c++ char exceptions

[Danny Smith]

Robert wrote:
>
> I don't know if this is a cygwin issue or if I am doing something
> fundamentally wrong...
>

You threw const char*

int
main (int argc, char **argv)
{
  try
    {
      throw "catch this";
    }
  catch (const char *message) 
//       ^^^^^ 
    {
      return 1;
    }
  return 0;
}

>

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RE: c++ char exceptions

[Robert Collins]

> -----Original Message-----
> From: Danny Smith [mailto:danny_r_smith_2001@yahoo.co.nz] 
> Sent: Tuesday, April 23, 2002 6:11 PM
> 
> Robert wrote:
> >
> > I don't know if this is a cygwin issue or if I am doing something 
> > fundamentally wrong...
> >
> 
> You threw const char*

Sigh. Blush. I should have caught (no pun intended) that. 

Thanks Danny.

Rob

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Re: c++ char exceptions

[Michael D. Crawford]

It aborts with g++ 2.95.4 on Debian PowerPC Linux too.

But if I compile it with CodeWarrior 6 on Windows it runs normally, doesn't 
crash, and gives the exit code of 1.

I think CodeWarrior is correct, and that this is a bug in g++, but not in cygwin.

Mike

Thus it was written:
I don't know if this is a cygwin issue or if I am doing something
fundamentally wrong...

int
main (int argc, char **argv)
{
   try
     {
       throw "catch this";
     }
   catch (char *message)
     {
       return 1;
     }
   return 0;
}

coredumps on me. Throwing int's works fine. Throwing (string) "foo"
works fine.
---

Michael D. Crawford
GoingWare Inc. - Expert Software Development and Consulting
http://www.goingware.com/
crawford@goingware.com

     Tilting at Windmills for a Better Tomorrow.


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Re: c++ char exceptions

[Michael D. Crawford]

 > You threw const char*

That shouldn't matter.  At the worst it should mean that the exception is not 
caught by any of the catch clauses given, so the "return 0" would be taken.

The only thing that should happen to an exception object after you're done with 
it is that objects thrown by value are destroyed.  In this case the pointer 
would be destroyed, but the memory it points to should not be deleted or anything.

Usually throwing a pointer is not what you really want to do, but it shouldn't 
cause a crash.

Michael D. Crawford
GoingWare Inc. - Expert Software Development and Consulting
http://www.goingware.com/
crawford@goingware.com

    Tilting at Windmills for a Better Tomorrow.



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Re: c++ char exceptions

[Lassi A. Tuura]

> That shouldn't matter.  At the worst it should mean that the exception is not
> caught by any of the catch clauses given, so the "return 0" would be taken.

It does matter -- in this case the exception was not handled, and
therefore terminate() gets called, which probably called abort().  That
is, the "return 0" is never taken, the exception leaks outside main().

//lat
-- 
Behold the turtle.  He makes progress only when
he sticks his neck out.  --James Bryant Conant

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Re: c++ char exceptions

[Michael D. Crawford]

You're right, I wasn't thinking, if an exception isn't caught before it
leaves main it aborts the program.

So maybe codewarrior has a bug!

Mike

On Tue, 2002-04-23 at 06:33, Lassi A. Tuura wrote:
> > That shouldn't matter.  At the worst it should mean that the exception is not
> > caught by any of the catch clauses given, so the "return 0" would be taken.
> 
> It does matter -- in this case the exception was not handled, and
> therefore terminate() gets called, which probably called abort().  That
> is, the "return 0" is never taken, the exception leaks outside main().
> 
> //lat
> -- 
> Behold the turtle.  He makes progress only when
> he sticks his neck out.  --James Bryant Conant
> 
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> 
-- 
Michael D. Crawford
GoingWare Inc. - Expert Software Development and Consulting
crawford@goingware.com
http://www.goingware.com/

     Tilting at Windmills for a Better Tomorrow.


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RE: c++ char exceptions

[Robert Collins]

> -----Original Message-----
> From: Michael D. Crawford [mailto:crawford@goingware.com] 
> Sent: Tuesday, April 23, 2002 6:24 PM
> 
> Usually throwing a pointer is not what you really want to do, 
> but it shouldn't 
> cause a crash.

Is it worth putting this up as a bug on the gcc bugs database?

Rob

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