[cfe-dev] initializer_list deduction

[David Blaikie]

On Wed, May 9, 2012 at 11:18 AM, Fernando Pelliccioni
<fpelliccioni at gmail.com> wrote:
> Hi all,
>
> Is it this behavior correct ?
>
> //Code ----------------------
> #include <initializer_list>
> #include <iostream>
> #include <string>
> #include <vector>
>
> using namespace std;
>
> void foo( initializer_list<typename vector<string>::value_type> list )
> {
>     for (auto& item : list)
>     {
>         cout << item << endl;
>     }
> }
>
> int main( /* int argc, char* argv[] */ )
> {
>     foo( { {"k0", "v0"}, {"k1", "v1"} } );
>     return 0;
> }
>
> //End code ----------------------
>
>
> $ clang++ --version
> clang version 3.1 (trunk 155038)
> Target: i386-pc-linux-gnu
> Thread model: posix
>
> $ clang++ -std=c++11 initializer_list_test.cpp
> $ ./a.out
> k0
> k1
>
> ------------------------------------------
>
> I would have expected that the initializer_list be deduced to something like
> an associative container (a compile time error).

I believe you're calling the std::string(Iterator begin, Iterator end)
constructor. As you could with this code:

std::string s{"k0", "v0"};

(or even C++03 code: std::string s("k0", "v0"); )

You probably got luck with the string constant layout & ran into "v0"
from "k0" - but I suspect the length of your strings is 3, not 2
(including the null character between "v0" and "k0")