Is the C++ Standard Library replaceable?

Question

Is the C++ standard library tied to the compiler or can a different implementation be provided?

I wonder about this mostly because it seems that the relation between the typeid keyword and std::type_info hinders this. The typeid keywords depends on the existence of std::type_info , which I would consider to be a dependency in the wrong direction. And I have no idea how a custom implementation should implement the type_info::name() method.

My questions are:

• Is the standard library replaceable?
• If yes, then how does one implement std::type_info

Answer 1

Yep, there are a variety of 'STLs':

• Original STL implementation by Stepanov and Lee. 1994, Hewlett-Packard. No longer maintained.
• SGI STL, based on original implementation by Stepanov & Lee. 1997, Silicon Graphics. No longer maintained.
• libstdc++ from gnu (was part of libg++)
• libc++ from clang
• STLPort, based on SGI STL
• Rogue Wave standard library (HP, SGI, SunSoft, Siemens-Nixdorf)
• Dinkum STL library by PJ Plauger

Edit:

Since this apparently is about the C++ Standard Library , there are some alternatives to that too:

• Apache C++ Standard Library ( http://stdcxx.apache.org/ )
• Dinkumware C++ Standard Library ( http://www.dinkumware.com/cpp.aspx )
• libc++ C++ Standard Library ( http://libcxx.llvm.org/ )
• GNU's libstdc++

Answer 2

Large parts of the library are independent of the compiler, like containers and algorithms.

Other parts are very much tied to a specific compiler, like you have found - type_info where the library rather documents what the compiler does rather than prescribes it.

Other similar examples might be bad_exception, std::size_t, and C++11 features like type_traits, atomics, and std::initializer_list, which all need support from the compiler. The library has to be closely matched to what a specific compiler actually does.

It is possible to write a library that works with several compilers, but not without tuning some low level code to each specific compiler. The libraries mentioned elsewhere does exactly that.

Answer 3

It is replaceable. Take a look into stl port

Answer 4

Yes, STL is not binded with compiler even though different compile has it's default STL implementation. You can generally change the STL implemtation by change some Project setting.

Eg In vS2008, you can do

Tools->Options->Project and Solutions -> VC++ Directoires -> Include fiels, add a different implementation(eg STL PORT), then move this line to the top(above the default implementation), then you have it.

Answer 5

另一个替代STL的例子，牺牲了一些符合标准的速度：EASTL（电子艺界） https://github.com/paulhodge/EASTL