Re: SegFault in 2**111111111 calculation

[Pearu Peterson]

On 6 Dec 2000, Torbjorn Granlund wrote:

> Pearu Peterson <address@hidden> writes:
> 
>   Calculating 2**111111111:
>   mp_allocate( 4 ) ->0x8049b80
>   Segmentation fault
>   
>   Is this a bug of GMP or anything else? Any hints how to get a control over
>   this SegFault are appreciated. Even if there is memory shortage (though
>   there shouldn't be, right?), I would expect a more graceful exit.
>   
> Some malloc packages return a valid pointer even if there is actually
> less VM available.  If the total VM usage of all processes on the
> system at some point gets greater than what is available, the system
> shots down on process with SIGSEGV.
> 
> I suspect that this is what happens on your GNU/Linux system.
> 
> If I am right, you should be able to make the program work by adding
> more swap.

Thanks for your interesting suggestion!

I am running Linux on a machine with 96MB physical memory and with a 256MB
swap. So, there should be plenty of VM. I even tried the reboot in order
to start with a fresh startup (with X and other stuff running there was
50MB free phys. memory available) but still with a SegFault crash. 

Have anybody tried this test on a different machine? Does it run at all?
Any estimates in MB how big is acctually 2**111111111?

Also note that SegFault happens before the malloc call (see the
supplied gmpy_allocate function).

Thanks,
        Pearu