Re: Are local structs illegal?

From:
"Bo Persson" <bop@gmb.dk>
Newsgroups:
comp.lang.c++.moderated
Date:
Wed, 13 Oct 2010 00:43:25 CST
Message-ID:
<8hk00aFtd6U1@mid.individual.net>
DeMarcus wrote:

Hi!

I'm using gcc 4.4.3. Is following illegal?

#include <vector>

void fnc()
{
   struct MyStruct
   {
      MyStruct() {}

      int someInt;
   };

   std::vector<MyStruct> vec;

   // Maybe do something with vec.
}

int main()
{
   fnc();

   return 0;
}

From above I get the following error message at the std::vector
line.
In function ??void fnc()??:
error: template argument for ??template<class _Tp> class
std::allocator?? uses local type ??fnc()::MyStruct??
error: trying to instantiate ??template<class _Tp> class
std::allocator?? error: template argument 2 is invalid
error: invalid type in declaration before ??;?? token

Are local structs illegal?


According to the current standard, local types cannot be used as template
arguments as they fail on the requirements of "external linkage".

This requirement will be relaxed in the next standard, C++0x.

Bo Persson

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