Can not declare std::map::iterator in template (error: expected `;' before "my_A_iterator")

William Gallafent william@gallaf.net
Thu Jan 17 09:20:00 GMT 2008


On 16 Jan 2008, at 15:36, Erik wrote:

> I have the strange problem that I can not declare a std::map::iterator
> inside a template:
>
> #include <map>
> template<typename S> struct A {};
> template<typename T> struct B {
>    typedef A<T> G;
>    void f(G const & a) {
>        std::map<G const *, int> my_As;
>        std::map<G const *, int>::iterator my_A_iterator =  
> my_As.find(&a);
>    }
> };
>
>
> The compiler says «error: expected `;' before "my_A_iterator"». If I
> change A<T> to for example bool, it compiles. What could possibly be
> wrong? I tried both g++-4.2.1 and g++-4.2.2.

Not a GCC problem, but a problem with the code: add the word  
"typename" to the beginning of that line to fix it.

See the language FAQ at http://www.parashift.com/c++-faq-lite/templates.html 
  for why ... question 35.18.

HTH,

-- 
Bill Gallafent.



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