Re: art backend : NSView crashes

[Fred Kiefer]

Looks like gcc 4.9 has gotten very strict about method calls on nil that return 
a structure. It has always been better to check that case, but now it has 
become a must.

Fred

On the road

Am 30.04.2015 um 23:42 schrieb Riccardo Mottola <riccardo.mottola@libero.it>:

> Hi,
> 
> Fred Kiefer wrote:
>> Where does this new crash come from? Does it give you a better stack trace?
> 
> I tried hard, I cannot reoproduce this on on another computer. On the 
> problematic computer (Gentoo linux, x86/32, libart 2.3.21 gcc 4.9.2)
> 
> - no optimizations (-g -O0) to compile PRICE -> no crash
> - -g -O1 or -O2, I get a useless trace:
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0xbfffcb89 in ?? ()
> (gdb) bt
> #0  0xbfffcb89 in ?? ()
> #1  0x00000000 in ?? ()
> 
> I think it is totally unrelated to GUI and BACK.
> PRICE's PRWindowController gets a notification and has this line:
> 
>  imgSize = [[[self document] activeImage] pixelSize];
> 
> this causes the crash. Supposing activeImage is nil, what pixelSize will I 
> get?
> Accessing a method on a nil object? and if that method doesn't return an 
> object but a struct?
> 
> I know that on SPARC accessing members of a NULL struct causes problems, but 
> the above?
> 
> 
> I substituted the code with this:
> 
>  img = [[self document] activeImage];
>  imgSize = NSZeroSize;
>  if (img)
>    imgSize = [img pixelSize];
> 
> and it works fine. What do you think?
> 
> Riccardo
> 
> _______________________________________________
> Discuss-gnustep mailing list
> Discuss-gnustep@gnu.org
> https://lists.gnu.org/mailman/listinfo/discuss-gnustep