Autotools check for C++11

Question

I use AX_CXX_COMPILE_STDCXX_0X(can look on autoconf-archive) to check for c++11 capabilities of the compiler. It correctly determines that -std=c++0x required, but does not add it to CXXFLAGS. I took a look at the macro source and it actually checks but then restores previous flags.

What should I do to get CXXFLAGS set to be able to compile c++11 source?

Just adding -std=c++0x to AM_CXXFLAGS is not nice solution, because I'd like to put the burden of making the compiler compile in C++11 mode on the autoconf developers, not me.

Answer 1

What you're looking for has already been made as AX_CXX_COMPILE_STDCXX_11, part of autoconf-archive. It will add the required option to the environment (formerly through CXXFLAGS, now through CXX) and error out if no C++11 support is available.

Answer 2

In general you can compile a simple code and set a variable based the outcome of your compilation

DIALECT="-std=c++14"
echo 'int main() {return 0;}' > ./log.cpp && $CXX -std=c++14 ./log.cpp || $DIALECT="no"

if test $DILAECT = no; then
    AC_MSG_ERROR([c++ compiler does not support c++14])
else
    echo $DILAECT
fi