Request for feature or bug?

I don't find anything in the documentation about that:
Should D make any run-time check whether a reference to an object is null
or not, before it calls a member function?

I wrote the attached program and it hangs up (CTRL-C can terminate :-)
if I left out the marked line.

Obviously there is a bug in my program in this case. The reference variable was created only and no physical object.

I think it is a typical problem for C++ programmers when starting to use D. First I tought the object instance will be created...

This bug can be caught only before the call is made to I_don't_know_where, the CPU does not call the member where the catch would also be possible.

A run-time check for null (with an exception thrown if needed) would be fine or is any other solution?

Thanks in advance,
Tamas

--------------------------
import c.stdio;

class xRecord{
int b;

this() {b=3;}
void set(int x)
{
if(this==null)
{
throw new Error("OOOooooppppsss !");
}
else
{
printf("The value of _this_: %p\n",this);
}
b=x;
}
}

void main(char[][] args)
{
xRecord xr2;
//    xr2=new xRecord();	//*********************************

printf("start\n");

if(xr2==null)
{
printf("xr2 is null\n");
}
else
{
printf("xr2 is: %p\n",xr2);
}

xr2.set(10); // hangs up if xr2 equals to null

printf("finish\n");
}
--------------------------------

Tamas Nagy
MicroWizard Ltd.
Hungary

"MicroWizard" <MicroWizard_member@pathlink.com> wrote in message news:ab38mr$2b7d$1@digitaldaemon.com...

> Should D make any run-time check whether a reference to an object is null or not, before it calls a member function?

I would suggest to put it into the same category as the array bounds check. It would be too slow in release builds, but when debugging, it would be nice to get a "member access by null reference at line #" error, instead of just "Access Violation at blablabla".

In article <ab3ak8$2cqj$1@digitaldaemon.com>, Pavel Minayev says...
>
>"MicroWizard" <MicroWizard_member@pathlink.com> wrote in message news:ab38mr$2b7d$1@digitaldaemon.com...
>
>> Should D make any run-time check whether a reference to an object is null or not, before it calls a member function?
>
>I would suggest to put it into the same category as the array bounds check. It would be too slow in release builds, but when debugging, it would be nice to get a "member access by null reference at line #" error, instead of just "Access Violation at blablabla".

I agree completely.

Tamas Nagy

"Pavel Minayev" <evilone@omen.ru> wrote in message news:ab3ak8$2cqj$1@digitaldaemon.com...
> "MicroWizard" <MicroWizard_member@pathlink.com> wrote in message news:ab38mr$2b7d$1@digitaldaemon.com...
>
> > Should D make any run-time check whether a reference to an object is
null
> > or not, before it calls a member function?
>
> I would suggest to put it into the same category as the array bounds check. It would be too slow in release builds, but when debugging, it would be nice to get a "member access by null reference at line #" error, instead of just "Access Violation at blablabla".
>


Agreed.

--
Stijn
OddesE_XYZ@hotmail.com
http://OddesE.cjb.net
_________________________________________________
Remove _XYZ from my address when replying by mail

Is there some distinction in the compiler/libraries between debug and release builds?

"Pavel Minayev" <evilone@omen.ru> wrote in message news:ab3ak8$2cqj$1@digitaldaemon.com...
> "MicroWizard" <MicroWizard_member@pathlink.com> wrote in message news:ab38mr$2b7d$1@digitaldaemon.com...
>
> > Should D make any run-time check whether a reference to an object is
null
> > or not, before it calls a member function?
>
> I would suggest to put it into the same category as the array bounds check. It would be too slow in release builds, but when debugging, it would be nice to get a "member access by null reference at line #" error, instead of just "Access Violation at blablabla".
>
>

"Matthew Wilson" <mwilson@nextgengaming.com> wrote in message news:ab7efd$fv9$1@digitaldaemon.com...

> Is there some distinction in the compiler/libraries between debug and release builds?

In release build, compiler removes all assertions, invariant calls and
unittests
from generated code. It also doesn't perform array bounds checks.

As for the library, currently, only debug version exist (with all checks
turned on), due to the alpha nature of the compiler. But I guess that, as
soon as Walter is sure there are no serious bugs left in there, he'll
do a recompile in release mode.