CODEWITHSUNDEEP
c++c++11c++14
Dietmar Kühl
Dietmar Kühl

Reputation: 153840

Is there a way to determine language features implemented by a C++ compiler?

Different C++ compilers implement the various language features at different points in time (see, e.g., clang C++ status and gcc c++ status; likewise for other compilers). When creating a C++ library it is often desirable to support the latest features to improve the user experience. When supporting new features rather than the common subset implemented everywhere it is helpful to know what features a compilers support without having to support a set of version numbers for each compiler.

Is there are reasonably standardized set of feature tests which can be used at compile time to determine if a specific language feature is supported by the compiler?

Upvotes: 2

Views: 271

Answers (2)

Sneftel
Sneftel

Reputation: 41484

You probably can't do better than the Boost.Config library. It defines preprocessor macros for various C++11 and C++14 features which aren't universally supported on C++11/14-ish compilers like VC++. It's as close as you're going to get to standard.

IIRC, it works similarly to autoconf, by prebuilding (and, when necessary, executing) a bunch of simple test programs. I don't think you're going to get anything which operates entirely at compile-time, simply because there are things which are keywords in one implementation and syntax errors in another.

Upvotes: 5

Dietmar Kühl
Dietmar Kühl

Reputation: 153840

I haven't tried to use the recommendations but at the C++ committee meetings the Feature Test SG (SG10) meets and updates a list of recommendations. Here is the latest document listing the current feature test macros: there are macros for various language level features. The expectation is that the document P0096rx will be updated when new features are voted into the working draft.

This document is not a standards document: the standard mandates implementation of a language standard and it doesn't make sense to standardize macros indicating whether a specific features is implemented! An implementation is either fully conforming or not. However, the expectation is that compiler vendors do use these macros as guidance to help users.

Upvotes: 3

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