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digitalmars.D - class.sizeof

reply "Denis Koroskin" <2korden gmail.com> writes:
I can't find a way to get a class sizeof property - it returns 4 (32bit  
pointer size) always. I tried many ways but still can't figure out how to  
do this. Documentation says that

".sizeof applied to a class object returns the size of the class  
reference, not the class instantiation."

Is it possible? Any idea is much appreciated.
Nov 14 2008
parent reply Tomas Lindquist Olsen <tomas famolsen.dk> writes:
Denis Koroskin wrote:

 I can't find a way to get a class sizeof property - it returns 4 (32bit 
 pointer size) always. I tried many ways but still can't figure out how 
 to do this. Documentation says that
 
 ".sizeof applied to a class object returns the size of the class 
 reference, not the class instantiation."
 
 Is it possible? Any idea is much appreciated.


No nice way to do it..

auto sz = myclass.classinfo.init.length;

problem this is not a compiletime constant,

In D2 you can use __traits to get it...

Kinda lame if you ask me :P

how about .instancesizeof ? I doubt that's even a remotely common variable name
...

-Tomas
Nov 14 2008
next sibling parent "Denis Koroskin" <2korden gmail.com> writes:
On Fri, 14 Nov 2008 21:06:39 +0300, Tomas Lindquist Olsen  
<tomas famolsen.dk> wrote:


 Denis Koroskin wrote:

 I can't find a way to get a class sizeof property - it returns 4 (32bit  
 pointer size) always. I tried many ways but still can't figure out how  
 to do this. Documentation says that
  ".sizeof applied to a class object returns the size of the class  
 reference, not the class instantiation."
  Is it possible? Any idea is much appreciated.


 No nice way to do it..

 auto sz = myclass.classinfo.init.length;

 problem this is not a compiletime constant,

 In D2 you can use __traits to get it...

 Kinda lame if you ask me :P

 how about .instancesizeof ? I doubt that's even a remotely common  
 variable name ...

 -Tomas


__traits trick works nice, thank you!

BTW, I found small inconsistency/bug:

template SizeOfPointee(T)
{
     static if (is (T t)) {
         enum SizeOfPointee = typeof(*t).sizeof;
     }
}

template SizeOfPointer(T)
{
     static if (is (T t)) {
         enum SizeOfPointer = typeof(t).sizeof;
     }
}

int i = SizeOfPointee!(int*); // works ok
int j = SizeOfPointer!(int*); // fails

I believe both should work.
Nov 14 2008
prev sibling parent reply Sean Kelly <sean invisibleduck.org> writes:
Tomas Lindquist Olsen wrote:

 Denis Koroskin wrote:

 I can't find a way to get a class sizeof property - it returns 4 
 (32bit pointer size) always. I tried many ways but still can't figure 
 out how to do this. Documentation says that

 ".sizeof applied to a class object returns the size of the class 
 reference, not the class instantiation."

 Is it possible? Any idea is much appreciated.


 
 No nice way to do it..
 
 auto sz = myclass.classinfo.init.length;
 
 problem this is not a compiletime constant,
 
 In D2 you can use __traits to get it...
 
 Kinda lame if you ask me :P
 
 how about .instancesizeof ? I doubt that's even a remotely common 
 variable name ...


I added an "isizeof" proposal to the issue tracker maybe two years ago. 
  Feel free to vote it up if you'd like.


Sean
Nov 14 2008
parent reply "Jarrett Billingsley" <jarrett.billingsley gmail.com> writes:
On Fri, Nov 14, 2008 at 2:35 PM, Sean Kelly <sean invisibleduck.org> wrote:

 Tomas Lindquist Olsen wrote:

 Denis Koroskin wrote:

 I can't find a way to get a class sizeof property - it returns 4 (32bit
 pointer size) always. I tried many ways but still can't figure out how to do
 this. Documentation says that

 ".sizeof applied to a class object returns the size of the class
 reference, not the class instantiation."

 Is it possible? Any idea is much appreciated.


 No nice way to do it..

 auto sz = myclass.classinfo.init.length;

 problem this is not a compiletime constant,

 In D2 you can use __traits to get it...

 Kinda lame if you ask me :P

 how about .instancesizeof ? I doubt that's even a remotely common variable
 name ...


 I added an "isizeof" proposal to the issue tracker maybe two years ago.
  Feel free to vote it up if you'd like.


But W will say "it's already accessible through __traits."  Not to
sound fatalistic, but do you honestly think this would be added to D1?
Nov 14 2008
next sibling parent "Tim M" <a b.com> writes:
A few years too late to by why isn't all classes objects, an instance of a  
special virtual class called Class.

On Sat, 15 Nov 2008 08:55:29 +1300, Jarrett Billingsley  
<jarrett.billingsley gmail.com> wrote:


 On Fri, Nov 14, 2008 at 2:35 PM, Sean Kelly <sean invisibleduck.org>  
 wrote:

 Tomas Lindquist Olsen wrote:

 Denis Koroskin wrote:

 I can't find a way to get a class sizeof property - it returns 4  
 (32bit
 pointer size) always. I tried many ways but still can't figure out  
 how to do
 this. Documentation says that

 ".sizeof applied to a class object returns the size of the class
 reference, not the class instantiation."

 Is it possible? Any idea is much appreciated.


 No nice way to do it..

 auto sz = myclass.classinfo.init.length;

 problem this is not a compiletime constant,

 In D2 you can use __traits to get it...

 Kinda lame if you ask me :P

 how about .instancesizeof ? I doubt that's even a remotely common  
 variable
 name ...


 I added an "isizeof" proposal to the issue tracker maybe two years ago.
  Feel free to vote it up if you'd like.


 But W will say "it's already accessible through __traits."  Not to
 sound fatalistic, but do you honestly think this would be added to D1?
Nov 14 2008
prev sibling next sibling parent bearophile <bearophileHUGS lycos.com> writes:
Jarrett Billingsley:

 But W will say "it's already accessible through __traits."  Not to
 sound fatalistic, but do you honestly think this would be added to D1?


Generally I think that having a fully frozen language (D1), that can't accept
improvements, is bad.
And I think that in an open source language, if enough people what to add a
feature or remove a bug, and they are able to implement/do it, then it has to
be doable. Begging a single person to implement all the changes or all
debugging seems silly. If enough people are willing, then such
feature/debugging can be added/done to LDC, for example.

Bye,
bearophile
Nov 14 2008
prev sibling parent Sean Kelly <sean invisibleduck.org> writes:
Jarrett Billingsley wrote:

 On Fri, Nov 14, 2008 at 2:35 PM, Sean Kelly <sean invisibleduck.org> wrote:

 I added an "isizeof" proposal to the issue tracker maybe two years ago.
  Feel free to vote it up if you'd like.


 
 But W will say "it's already accessible through __traits."  Not to
 sound fatalistic, but do you honestly think this would be added to D1?


I don't :-)  If it were, it would have been added already.


Sean
Nov 14 2008