Catching a hot potato

[Steven Schveighoffer]

On Sat, 15 Oct 2011 08:18:59 -0400, Gor Gyolchanyan  
<gor.f.gyolchanyan at gmail.com> wrote:

> Thanks for the detailed answer.
> Example of when i would like to recover from a segfault:
> I have different independent parts of an app, which MAY cooperate. If,
> however, one of them crashes (e.g. they come from different sources)
> the other one will continue to work but without the cooperation
> functionality.

A segfault means something has attempted reading/writing to a memory  
location that was not allocated.  Note that this does *not* necessarily  
mean dereferencing null.

The worst case scenario is that something has invalidly written to  
*allocated* memory before your program reads from/writes to unallocated  
memory.  Usually this is a result of the usage of the now-corrupted  
allocated memory.

For instance, a module that caused the segfault might *not* be the module  
which misbehaved!  It could have been a rogue third module which corrupted  
the memory in the segfaulting module.  Closing the segfaulting module does  
no good.

Catching a segfault and continuing the program is a very bad idea.  You  
have no idea what valid memory was corrupted before the segfault occurred,  
or who did it.  The only logical thing to do is exit the program, maybe  
attempting to print a stack trace (which might fail if the stack is  
corrupt).

-Steve