How to Enable C++11 Features in Codelite

问题:

The following code compiles and runs in Xcode 5 and in Visual Studio 2013. I am interested in trying out Codelite, but Codelite will not compile the following program (a problem since I am working with scoped enums in my project). As far as I understand it, Codelite is using the same compiler as Xcode.

Is the code valid per C++11? Why is Codelite unable to compile it?

#include <iostream>

namespace abc
{
    namespace xyz
    {
        enum class SampleEnum
        {
            SomeValue = 0,
            SomeOtherValue = 1
        };
    }
}

int main(int argc, char **argv)
{
    abc::xyz::SampleEnum e = abc::xyz::SampleEnum::SomeValue;
    return 0;
}

Here is the build output from Codelite. In case it's garbled, it's pointing to the word "SampleEnum" in the instantiation of the variable and saying "expected a class or namespace".

/bin/sh -c 'make -j8 -e -f  Makefile'
----------Building project:[ ClangTest - Debug ]----------
codelite-cc /usr/bin/clang++   -c  "/Users/xxx/Desktop/Test/ClangTest/main.cpp" -g -O0 -Wall  -o ./Debug/main.cpp.o -I. -I.
/Users/xxx/Desktop/Test/ClangTest/main.cpp:7:8: warning: scoped enumerations are a C++11 extension [-Wc++11-extensions]
                enum class SampleEnum
                     ^
/Users/xxx/Desktop/Test/ClangTest/main.cpp:17:40: error: expected a class or namespace
    abc::xyz::SampleEnum e = abc::xyz::SampleEnum::SomeValue;
                             ~~~~~~~~~~^
1 warning and 1 error generated.
make[1]: *** [Debug/main.cpp.o] Error 1
make: *** [All] Error 2
2 errors, 1 warnings

回答1:

It is necessary to pass -std=c++11 to the compiler to enable C++11 features. Here are the steps to do so in Codelite:

• Right click on the project in the workspace view.
• Select Settings near the bottom of this pop-up menu. Common Settings->Compiler->C++ Compiler Options
• Click into the semicolon delimited list of compiler switches to reveal elipses and click on the elipses.
• Click the checkbox for -std=c++11

回答2:

If you are using C++11 extensions, compilers want it to be flagged. Without it they may throw warnings and errors. That's because some of C++11 changes are not backward-compatible, e.g. the use of auto.

For example, in gcc you should have

gcc -std=c++11

Check if your compiler shouldn't have such parameter as well!

回答3:

I suppose this is because that your default std version is not c++11. To change to c++11, if you are using your terminal, you should type in the following command:

g++ yourfile.cpp -std=c++11