null dereference

[luka8088]

On 15.3.2014. 16:37, Adam D. Ruppe wrote:
> There is a hidden module on Linux which can activate this, sort of:
> 
> void main() {
>    // these two lines turn it on
>    import etc.linux.memoryerror;
>    registerMemoryErrorHandler();
> 
>    Object o = null;
>    o.toString(); // trigger it here
> }
> 
> etc.linux.memoryerror.NullPointerError at src/etc/linux/memoryerror.d(325):
> ----------------
> ../test56(void etc.linux.memoryerror.sigsegvDataHandler()+0xb) [0x805d44b]
> ../test56(_Dmain+0xa) [0x805c8ea]
> ../test56(void rt.dmain2._d_run_main(int, char**, extern (C) int
> function(char[][])*).runAll().void __lambda1()+0x10) [0x805cb58]
> ../test56(void rt.dmain2._d_run_main(int, char**, extern (C) int
> function(char[][])*).tryExec(scope void delegate())+0x18) [0x805cad0]
> ../test56(void rt.dmain2._d_run_main(int, char**, extern (C) int
> function(char[][])*).runAll()+0x27) [0x805cb1f]
> ../test56(void rt.dmain2._d_run_main(int, char**, extern (C) int
> function(char[][])*).tryExec(scope void delegate())+0x18) [0x805cad0]
> ../test56(_d_run_main+0x117) [0x805ca67]
> ../test56(main+0x14) [0x805c90c]
> /lib/libc.so.6(__libc_start_main+0xe6) [0xf75f3b86]
> ../test56() [0x805c831]
> 
> 
> 
> 
> As you can see there, the top line doesn't really help much, it just
> lists the  druntime module, but the stack trace can help: it shows
> _Dmain in there, and if you add other functions, you can see them too.
> 
> So still not quite a file+line number for the exact place (you can get
> that in a debugger fairly easily though) but helps find where it is,
> especially if you have fairly small functions.

I was not aware of this. Thanks!