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digitalmars.D - interfacing c++ templates. Another c++-namespace issue?

reply Markus <contact markus-lanner.com> writes:
Hi

[template.cpp]:
template<typename Type>
void some_templated_function();

template<>
void some_templated_function<int>()
{}

[main.d]:
extern(C++) {
   void some_templated_function(Type)();
}

void main() {
   some_templated_function!int;
}

compilation:
g++ -c template_with_ns.cpp
dmd main.d template.o

this WORKS! :) BUT, now I put all c++ stuff into a namespace
[template_with_ns.cpp]:
namespace some_namespace {

template<typename Type>
void some_templated_function();

template<>
void some_templated_function<int>()
{}

}

[main_with_ns.d]:
extern(C++, some_namespace) {
   void some_templated_function(Type)();
}

void main() {
   some_templated_function!int;
}

DOES NOT compile
undefined reference to `void some_templated_function<int>()'

nm main_with_ns.o
_Z23some_templated_functionIiEvv
nm template_with_ns.o
_ZN14some_namespace23some_templated_functionIiEEvv

It seems like dmd doesn't care about the namespace of the 
template.
Can someone confirm this as a bug? or am I doing something 
terrible wrong? :)

When I retry this with gdc it doesn't compile. Neither with 
namespace nor without:
nm template.o:
_Z23some_templated_functionIiEvv
main.o:
_ZN23some_templated_functionIiE23some_templated_functionEv

The more I work with D, interfacing C++, the more I start to know 
"mangling" :D

Have fun
Markus
Mar 16 2018
parent reply Walter Bright <newshound2 digitalmars.com> writes:
On 3/16/2018 11:57 AM, Markus wrote:

 It seems like dmd doesn't care about the namespace of the template.
 Can someone confirm this as a bug? or am I doing something terrible wrong? :)


Might check that this https://issues.dlang.org/show_bug.cgi?id=17772 is not the 
issue. See my comment in https://github.com/dlang/dmd/pull/7906 :

"Fixing the T_ mangling is much more problematic, I don't know how to do that 
yet. This namespace issue is independent, so it is convenient to do it
separately."
Mar 16 2018
parent reply Steven Schveighoffer <schveiguy yahoo.com> writes:
On 3/16/18 3:32 PM, Walter Bright wrote:

 On 3/16/2018 11:57 AM, Markus wrote:

 It seems like dmd doesn't care about the namespace of the template.
 Can someone confirm this as a bug? or am I doing something terrible 
 wrong? :)


 
 Might check that this https://issues.dlang.org/show_bug.cgi?id=17772 is 
 not the issue. See my comment in https://github.com/dlang/dmd/pull/7906 :
 
 "Fixing the T_ mangling is much more problematic, I don't know how to do 
 that yet. This namespace issue is independent, so it is convenient to do 
 it separately."


There was another namespace issue recently found:

https://issues.dlang.org/show_bug.cgi?id=18582

But it looks like its different. When you compare:

C++:
_ZN14some_namespace23some_templated_functionIiEEvv

D:
_ZN23some_templated_functionIiE23some_templated_functionEv

Something is wrong. Instead of the namespace, you get 
"some_templated_function" as the namespace!

-Steve
Mar 16 2018
parent "H. S. Teoh" <hsteoh quickfur.ath.cx> writes:
On Fri, Mar 16, 2018 at 03:53:00PM -0400, Steven Schveighoffer via
Digitalmars-d wrote:
[...]

 There was another namespace issue recently found:
 
 https://issues.dlang.org/show_bug.cgi?id=18582
 
 But it looks like its different. When you compare:
 
 C++:
 _ZN14some_namespace23some_templated_functionIiEEvv
 
 D:
 _ZN23some_templated_functionIiE23some_templated_functionEv
 
 Something is wrong. Instead of the namespace, you get
 "some_templated_function" as the namespace!


[...]

I wonder if the problem is caused by wrongly treating the template
function as a D eponymous template instead of a C++ template?


T

-- 
Don't drink and derive. Alcohol and algebra don't mix.
Mar 16 2018