This script prints the supported and announced features of the C++ compiler and library, including experimental features. It relies on the required functionality of C++ compilers to define macros with the prefix __cpp as appropriate. The values of the macros indicate the date of the specification of the features. The value of the same macro can have multiple dates, indicating multiple revisions of the feature definition. Later definitions are backward-compatible with earlier versions which means the values can be used in static_assert statements to ensure the compilation environment has the necessary support.

__static_assert(__cpp_lambdas >= 200907);

The script can be used with an optional argument indicating which standard should be used.

c++-features.sh

This invocation shows the features according to the default version of the compiler.

c++-features.sh gnu++2a

This invocation on the other hand shows the support for the (upcoming) C++20 standard along with the GNU extensions, if any.

By default, g++ is used as the compiler. It is possible to select a different compiler using the CXX environment variable.

CXX=clang++ c++-features.sh c++17

This command shows the support for C++17 in the Clang compiler

If the script is given two version numbers the output describes the difference in feature macros between the two version.

To make it easier to specify the version number a bash completion script is provided. To enable it add something like this to the shell profile scripts:

 . ~/path/to/c++-features-completion.bash

Author: Ulrich Drepper [email protected]