"to_string" isn't a member of "std"?

Question

Okay, so I have

tmp.cpp:

#include <string>

int main()
{
    std::to_string(0);
    return 0;
}

But when I try to compile I get:

$ g++ tmp.cpp -o tmp
tmp.cpp: In function ‘int main()’:
tmp.cpp:5:5: error: ‘to_string’ is not a member of ‘std’
     std::to_string(0);
     ^

I'm running g++ version 4.8.1. Unlike all the other references to this error that I found out there, I am not using MinGW, I'm on Linux (3.11.2).

Any ideas why this is happening? Is this standard behaviour and I did something wrong or is there a bug somewhere?

Solution 1

you may want to specify the C++ version with

g++ -std=c++11 tmp.cpp -o tmp

I don't have gcc 4.8.1 at hand , but in older versions of GCC, you can use

g++ -std=c++0x tmp.cpp -o tmp

At least gcc 4.9.2 I believe also support part of C++14 by specifying

g++ -std=c++1y tmp.cpp -o tmp

Update: gcc 5.3.0 (I am using the cygwin version) supports both -std=c++14 and -std=c++17 now.

Solution 2

to_string works with the latest C++ versions like version 11. For older versions you can try using this function

#include <string>
#include <sstream>

template <typename T>
std::string ToString(T val)
{
    std::stringstream stream;
    stream << val;
    return stream.str();
}

By adding a template you can use any data type too. You have to include #include<sstream> here.

Comments

[M.M]

With g++ -std=c++11 -o tmp tmp.cc, I get `error: 'to_string' is not a member of 'std'. g++ version is 4.8.2 . Is this a regression?

[mueslo]

Mh, not sure, but it works for me on g++ 4.9.0

[Brian Jack]

gcc --version using gcc tdm-2 4.8.1, compiling with -std=c++11 still yields error 'to-string' is not member of std

[Alain1405]

Same for me. With arm-none-eabi-gcc -std=c++11 I still get the error.

[eluong]

Had this error in Eclipse CDT on Debian 8 (Linux 3.14-2-amd64). Specifying the GCC C++ Compiler in the settings to run the command g++ -std=c++11 solved my issue! Thank you!

[Brian Jack]

I still get the error in gcc --version tdm-2 4.8.1 when compiling with -std=c++11

[Max Raskin]

I've also encountered this issue, it seems that std::to_string isn't available in gcc's standard library (libstdc++), it is however, available in libc++ which comes with LLVM/clang

[CS Pei]

what version of gcc you are using, you may also try -std=c++1y

[Bruno Bieri]

wouldn't it be more safe to use std::ostringstream since we only want the output of the stream?