compilation error using constexpr in C++

Question

I'm trying to use constexpr in C++ but get the compile error: 'constexpr' was not declared in this scope.

I tried both in CodeBlocks using the GNU GCC compiler, and in Visual Studio 2013.

the code is:

#include <iostream>

int main()
{
    constexpr double ft2m = 0.3048;
    std::cout << ft2m;
}

What could be the problem?

I'm going guess that you need to change your compiler settings so that it compiles against the C++11 standard. — R Sahu
– R Sahu, Commented Mar 6, 2017 at 7:55

qianfg · Accepted Answer · 2017-03-06 07:54:54Z

2

What version of gcc are you using?

You might need at -std=c++11 to your command line

answered Mar 6, 2017 at 7:54

qianfg

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Comments

Bathsheba · Accepted Answer · 2017-03-06 07:55:11Z

2

The problem is that MSVC2013 does not support constexpr. It does not purport to implement the C++11 standard.

The first version that does is MSVC2015.

Your constexpr statement is grammatically correct C++11. Make sure you have a GCC version compliant with that standard.

answered Mar 6, 2017 at 7:55

Bathsheba

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