Using map::at() in pre c++0x

Question

I was happy see that map::at() was added to c++11, but upon digging around, I see that's it's already defined in gcc libraries, and works with -std=c++0x, and c++98.

Is using this method for code compiled with a standard before c++0x considered portable?

Answer 1

I think you are misinterpreting what -std=c++0x means. From C dialect options :

'c++11'

'c++0x'

The 2011 ISO C++ standard plus amendments. Support for C++11 is still experimental, and may change in incompatible ways in future releases. The name 'c++0x' is deprecated.

As you can see c++0x and c++11 are equivalent and c++0x is deprecated.