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digitalmars.D.learn - attribute decl in version decl

reply Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
Just came across some old D code that does this:

version(linux){
	extern(C):
}

<Hundreds of OpenGL decls>



in dmd 2.055, the extern(C) is not being applied to the OpenGL decls.
should it?
Sep 18 2011
next sibling parent reply Timon Gehr <timon.gehr gmx.ch> writes:
On 09/18/2011 06:55 PM, Ellery Newcomer wrote:

 Just came across some old D code that does this:

 version(linux){
 	extern(C):
 }

 <Hundreds of OpenGL decls>



 in dmd 2.055, the extern(C) is not being applied to the OpenGL decls.
 should it?


Yes they should be applied, unless they declare D functions, which is 
seldom the case for <Hundreds of OpenGL decls>.

If you are asking, if the D compiler is wrong here: No, it is by design, 
you can check with the D grammar.
Sep 18 2011
parent reply Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 09/18/2011 01:02 PM, Timon Gehr wrote:

 
 If you are asking, if the D compiler is wrong here: No, it is by design,
 you can check with the D grammar.


Nah, just confirming that failure to apply the externs is a bug.
Sep 18 2011
parent Timon Gehr <timon.gehr gmx.ch> writes:
On 09/18/2011 10:46 PM, Ellery Newcomer wrote:

 On 09/18/2011 01:02 PM, Timon Gehr wrote:

 If you are asking, if the D compiler is wrong here: No, it is by design,
 you can check with the D grammar.


 Nah, just confirming that failure to apply the externs is a bug.


version(linux){
     extern(C):
} // affected declarations end here, because '}' is not a declaration.

ConditionalDeclarations don't work like the C preprocessor, the code is 
parsed before the ConditionalDeclaration is applied, not the other way 
round.

It would indeed be desirable to have it work like this, but it would be 
a special case.
Sep 18 2011
prev sibling next sibling parent reply Trass3r <un known.com> writes:
Am 18.09.2011, 18:55 Uhr, schrieb Ellery Newcomer  
<ellery-newcomer utulsa.edu>:


 Just came across some old D code that does this:

 version(linux){
 	extern(C):
 }

 <Hundreds of OpenGL decls>



 in dmd 2.055, the extern(C) is not being applied to the OpenGL decls.
 should it?


Walter once said it was deliberate.
That extern(C) is only valid inside the version block.
But I also think it should be the other way around.
Sep 18 2011
parent Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 09/18/2011 04:09 PM, Trass3r wrote:

 Am 18.09.2011, 18:55 Uhr, schrieb Ellery Newcomer
 <ellery-newcomer utulsa.edu>:
 

 Just came across some old D code that does this:

 version(linux){
     extern(C):
 }

 <Hundreds of OpenGL decls>



 in dmd 2.055, the extern(C) is not being applied to the OpenGL decls.
 should it?


 
 Walter once said it was deliberate.
 That extern(C) is only valid inside the version block.
 But I also think it should be the other way around.


Really.

Wonder how gunroar ever compiled
Sep 18 2011
prev sibling next sibling parent reply "Daniel Murphy" <yebblies nospamgmail.com> writes:
"Ellery Newcomer" <ellery-newcomer utulsa.edu> wrote in message 
news:j557r6$vgt$1 digitalmars.com...

 Just came across some old D code that does this:

 version(linux){
 extern(C):
 }


Are the prototypes extern(Windows) when not on linux, by any chance?  That 
is the only combination I've ever had to use, and is supported by 
extern(System).
Sep 18 2011
parent Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 09/18/2011 11:04 PM, Daniel Murphy wrote:

 "Ellery Newcomer" <ellery-newcomer utulsa.edu> wrote in message 
 news:j557r6$vgt$1 digitalmars.com...

 Just came across some old D code that does this:

 version(linux){
 extern(C):
 }


 
 Are the prototypes extern(Windows) when not on linux, by any chance?  That 
 is the only combination I've ever had to use, and is supported by 
 extern(System). 
 
 


yep. didn't know about System. Thanks.
Sep 19 2011
prev sibling parent reply Mike Parker <aldacron gmail.com> writes:
On 9/19/2011 1:55 AM, Ellery Newcomer wrote:

 Just came across some old D code that does this:

 version(linux){
 	extern(C):
 }

 <Hundreds of OpenGL decls>



 in dmd 2.055, the extern(C) is not being applied to the OpenGL decls.
 should it?


Change it to the following, and you're golden.

extern(System):

<Hundreds of OpenGL decls>
Sep 19 2011
parent reply Trass3r <un known.com> writes:
 Change it to the following, and you're golden.

 extern(System):

 <Hundreds of OpenGL decls>


That only fixes this particular issue.

I once had the following case that can't be done:

version(V1)
{
	extern(System):
}
else
{
	extern(C):
}
Sep 19 2011
parent reply Timon Gehr <timon.gehr gmx.ch> writes:
On 09/19/2011 03:37 PM, Trass3r wrote:

 Change it to the following, and you're golden.

 extern(System):

 <Hundreds of OpenGL decls>


 That only fixes this particular issue.

 I once had the following case that can't be done:

 version(V1)
 {
 extern(System):
 }
 else
 {
 extern(C):
 }


You could use the C preprocessor ;). Or this, that does the same thing:

version(V1) private enum _v1=true;
else private enum _v1=false;
mixin((_v1?"extern(System):":"extern(C):")~q{
     // all declarations that should be affected.
});
Sep 19 2011
parent Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 09/19/2011 08:59 AM, Timon Gehr wrote:

 
 You could use the C preprocessor ;). Or this, that does the same thing:
 
 version(V1) private enum _v1=true;
 else private enum _v1=false;
 mixin((_v1?"extern(System):":"extern(C):")~q{
     // all declarations that should be affected.
 });


<code golf>

or this:

version(linux){
 extern(C):
  mixin(s);
}
version(Win32){
 extern(Windows):
 mixin(s);
}

enum s = q{
 <hundreds of opengl decls>
};

</code golf>
Sep 19 2011