What could C/C++ “lose” if they defined a standard ABI?

Question

The title says everything. I am talking about C/C++ specifically, because both consider this as \"implementation issue\". I think, defining a standard interface can ease bui

Answer 1

Basically, everyone missed that one of the C++14 proposals actually DID define a standard ABI. It was a standard ABI specifically for libraries that used a subset of C++. You define specific sections of "ABI" code (like a namespace) and it's required to conform to the subset.

Not only that, it was written by THE Herb Stutter, C++ expert and author the "Exceptional C++" book series.

The proposal goes into many reasons why a portable ABI is difficult, as well as novel solutions.

https://isocpp.org/blog/2014/05/n4028

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4028.pdf

Note that he defines a "target platform" to be a combination of CPU architecture (x64, x86, ARM, etc), OS, and bitness (32/64).

So the goal here, is actually having C++ code (Visual Studio) be able to talk to other C++ code (GCC, older Visual Studio, etc) on the same platform. It's not a goal of a universal ABI that lets cellphones libraries run on your Windows machine.

This proposal was NOT ratified in C++14, however, it was moved into the "Evolution" phase of C++17 for further discussion/iteration.

https://www.ibm.com/developerworks/community/blogs/5894415f-be62-4bc0-81c5-3956e82276f3/entry/c_14_is_ratified_the_view_from_the_june_2014_c_standard_meeting?lang=en

So as of January 2017, my fingers remain crossed.

Answer 2

Well, there wouldn't be one standard ABI, but about 1000. You would need one for every combination of OS and processor architecture.

Initially, nothing would be lost. But eventually, somebody would find some horrible bug and they would either fix it, breaking the ABI, or leave it, causing problems.

I think that the situation right now is fine. Any OS is free to define an ABI for itself (and they do), which makes sense. It should be the job of the OS to define its ABI, not the C/C++ standard.