• Thomas Kuehne (16/16) Dec 01 2004 -----BEGIN PGP SIGNED MESSAGE-----
• Regan Heath (20/27) Dec 01 2004 Try this instead:
• Thomas Kuehne (17/44) Dec 01 2004 -----BEGIN PGP SIGNED MESSAGE-----
• Regan Heath (22/72) Dec 01 2004 For classes but not for structs. For structs you are supposed to be able...

Thomas Kuehne <thomas-dloop kuehne.thisisspam.cn> writes:

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struct.<field>.offsetof is not supported.

struct.html:




test case:
http://svn.kuehne.cn/dstress/run/offsetof_01.d

Thomas


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"Regan Heath" <regan netwin.co.nz> writes:

On Wed, 1 Dec 2004 13:31:31 +0100, Thomas Kuehne  
<thomas-dloop kuehne.thisisspam.cn> wrote:
 struct.<field>.offsetof is not supported.

 struct.html:




 test case:
 http://svn.kuehne.cn/dstress/run/offsetof_01.d

Try this instead:

// $HeadURL$
// $Date$
// $Author$

module dstress.run.offsetof_01;

struct MyStruct{
	int a;
	int b;	
}

int main(){
	assert(MyStruct.a.offsetof >= 0);
	assert(MyStruct.b.offsetof >= 0);
	assert(MyStruct.a.offsetof != MyStruct.b.offsetof);

	return 0;
}

IIRC this property applies to the struct definition *not* the struct  
instance.

Regan

Thomas Kuehne <thomas-dloop kuehne.thisisspam.cn> writes:

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Regan Heath schrieb am Thu, 02 Dec 2004 09:54:55 +1300:
 On Wed, 1 Dec 2004 13:31:31 +0100, Thomas Kuehne  
 struct.<field>.offsetof is not supported.

 struct.html:




 test case:
 http://svn.kuehne.cn/dstress/run/offsetof_01.d

 Try this instead:

 // $HeadURL$
 // $Date$
 // $Author$

 module dstress.run.offsetof_01;

 struct MyStruct{
 	int a;
 	int b;	
 }

 int main(){
 	assert(MyStruct.a.offsetof >= 0);
 	assert(MyStruct.b.offsetof >= 0);
 	assert(MyStruct.a.offsetof != MyStruct.b.offsetof);

 	return 0;
 }

 IIRC this property applies to the struct definition *not* the struct  
 instance.

That's strange. For classes it's the other way round: the property
applies only to the instance and not the class definition !?

I can come up with an explanation why - under some uncommon
circumstances - the offsetof property can only be determined for
instances.

Why should a property that is available for the definition not be
available for the instance?

Thomas


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"Regan Heath" <regan netwin.co.nz> writes:

On Wed, 1 Dec 2004 22:09:07 +0100, Thomas Kuehne  
<thomas-dloop kuehne.thisisspam.cn> wrote:
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 Hash: SHA1

 Regan Heath schrieb am Thu, 02 Dec 2004 09:54:55 +1300:
 On Wed, 1 Dec 2004 13:31:31 +0100, Thomas Kuehne
 struct.<field>.offsetof is not supported.

 struct.html:




 test case:
 http://svn.kuehne.cn/dstress/run/offsetof_01.d

 Try this instead:

 // $HeadURL$
 // $Date$
 // $Author$

 module dstress.run.offsetof_01;

 struct MyStruct{
 	int a;
 	int b;	
 }

 int main(){
 	assert(MyStruct.a.offsetof >= 0);
 	assert(MyStruct.b.offsetof >= 0);
 	assert(MyStruct.a.offsetof != MyStruct.b.offsetof);

 	return 0;
 }

 IIRC this property applies to the struct definition *not* the struct
 instance.

 That's strange. For classes it's the other way round: the property
 applies only to the instance and not the class definition !?

 I can come up with an explanation why - under some uncommon
 circumstances - the offsetof property can only be determined for
 instances.

For classes but not for structs. For structs you are supposed to be able  
to align and lay them out how you want. So at compile time the offsets are  
known. I suspect that is why the definition is used for structs and the  
instance for classes.

 Why should a property that is available for the definition not be
 available for the instance?

Good question. If it's available for the definition then surely it can be  
made available for the instance.. it might be an optimisation thing, why  
store the info 'in' the struct when it's not required. However surely some  
compiler trickery could deduce the struct type from the instance and turn..

struct foobar {
   int a;
}

foobar b;
b.a.offsetof


into..

struct foobar {
   int a;
}

foobar b;
foobar.a.offsetof

Regan


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