Catching a hot potato

[Steven Schveighoffer]

On Mon, 17 Oct 2011 00:54:31 -0400, Gor Gyolchanyan  
<gor.f.gyolchanyan at gmail.com> wrote:

> If the user tries to read unallocated memory, the memory can't
> possibly get corrupted, since nothing is getting changed.
> If the user tried to write to unallocated memory, the segfault should
> _prevent_ it by throwing an OS-level exception (the sigsegv). Throwing
> if _after_ the invalid write makes no sense. You can't save anything,
> because your own data is not touched. Depending on the implementation,
> either some other process's memory would be touched or nothing at all
> (internally unmapped region).
> I think the rumors of corrupted memory after sigsegv is boloney.
> Otherwise the whole sigsegv idea is pointless (you could just as well
> get terminated right away).

sigsegv is often the *symptom*, not the *cause* of corrupted memory.

Of course sigsegv cannot corrupt memory.  But corrupted memory often makes  
a segv occur (and quite often not anywhere near where the real problem is).

It's why memory corruption is the *worst* bug to deal with.

Your best bet is to close the application, and possibly print a stack  
trace.  Trying to continue is like continuing to drive when you get a flat  
tire.  You are just going to keep damaging your car!

-Steve