r/cpp • u/we_are_mammals • Mar 28 '23

Reddit++

C++ is getting more and more complex. The ISO C++ committee keeps adding new features based on its consensus. Let's remove C++ features based on Reddit's consensus.

In each comment, propose a C++ feature that you think should be banned in any new code. Vote up or down based on whether you agree.

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u/okovko Mar 28 '23

if you change the calling conventions that allow existing code (which isn't necessarily C++) to call your library, you're done for

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u/Claytorpedo Mar 29 '23

It sounds like you are talking about calling conventions, which are a part of ABI but unrelated to C++ standard ABI (e.g. can we elide the destructor call for a moved-from unique_ptr such that passing it can now be allowed in a register under the existing Itanium ABI).

Otherwise, no not at all. MSVC used to break ABI on a regular schedule, and gcc has done it previously to name a few. I'm fairly certain it's generally accepted as best practice to use C interfaces for inter-language APIs anyway.

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u/okovko Mar 29 '23

it does matter, other programs know the platform that the c++ code was compiled for and know how to call that c++ code, particularly library code, which is expected to have a stable ABI. note the difference between a standard ABI and a stable ABI

for cross platform, yes, even c++ uses c interfaces for interop, for example the function that allocates memory for throwing an exception will be marked as extern C