Is Gcc 4.8.1 C++11 Complete?
Os Is Windows. I'll Start off by Saying That I Have No Experience with C++, or Any Other Compiled Language. I've Used Cpython a Bit and Am Familiar with That...
OS is windows.
I'll start off by saying that I have no experience with C++, or any other compiled language. I've used CPython a bit and am familiar with that, but, until earlier today, I'd never even glanced at C++ source.
I'm trying to teach myself C++, so I've been playing around with it a bit, and one problem I'm having is the error:
error: 'to_string' was not declared in this scope
Apparently, to_string is a C++11 thing, which should be fine. I downloaded the latest MinGW, added it to my path - I have checked, and running
g++ - v
does indeed tell me that I have version 4.8.1 installed. The IDE I'm working with, Code::Blocks finds it no problem, but it simply won't use any of the C++11 stuff, giving me errors such as the one above. Things not exclusive to C++11 compile fine.
There is a section under compiler flags to "follow the C++11 language standard", which I have checked, but, even then, I get the same errors. I'm really not sure what's going on - I've looked this up, and all of the suggestions are to update either the IDE or MinGW (both of which are up to date), or to select that flag, which, as I said, is already selected.
Does anyone with more experience with C++ have any idea what might be going on?b
4 Answers
My understanding is that, other than regex support, G++'s C++11 support is largely complete with 4.8.1.
The following two links highlight the status of C++11 support in G++ 4.8.1 and libstdc++:
- C++11 status in GCC 4.8.x.
- C++11 status in libstdc++. Note that this is for the latest SVN release, not tied to a specific G++ release; therefore expect it to be "optimistic" with respect to G++.
To compile C++11 code, though, you need to include the command line flag -std=c++11 when you compile.
The g++ 4.8 series was not complete with regard to the core language. The following compiles and runs with g++ 4.9 and higher (and also with clang++ 3.3 and higher), but not with g++ 4.8.5 (or with any previous member of the g++ 4.8 series).
#include <iostream>
void ordinary_function (int&) { std::cout << "ordinary_function(int&)\n"; }
void ordinary_function (int&&) { std::cout << "ordinary_function(int&&)\n"; }
template<class T>
void template_function (T&) { std::cout << "template_function(T&)\n"; }
template<class T>
void template_function (T&&) { std::cout << "template_function(T&&)\n"; }
int main () {
int i = 42;
ordinary_function(42); // Not ambiguous.
ordinary_function(i); // Not ambiguous.
template_function(42); // Not ambiguous.
template_function(i); // Ambiguous in g++4.8.
}
std::string is not compliant; it still uses legacy (and buggy especially with threads) 'copy on write' behavior. You might be able to use __gnu_cxx::__vstring as a workaround.
"Class template basic_string Partial Non-conforming Copy-On-Write implementation"
The behavior of std::string and std::list is not conforming C++11 standard. The document of libstdc++ is here [ ]
A macro named _GLIBCXX_USE_CXX11_ABI can control the behavior of them in GCC5/higher.
Besides that, C++11 std::function in GCC-4.8 is different from GCC-5 and higher version, and there is no macro can control the behavior of std::function.
[ Undocumented ABI changes of std::function between GCC-4 and GCC-5/6/7/8/9, how to make a .so working with devtoolset-4/6/7/8/9? ]
The C++11 in GCC-4.8 is considered as experimental support, so do not depend on it much.
Alexander Ross has covered the video game industry for a decade, writing deep dives on game design, esports tournaments, VR developments, and gaming culture.
