What's the pro of not having a stable ABI?
Being able to change things. It's like all downsides of backwards compatibility but on a binary level
As to things ABI prevents:
- scoped_lock was added to not break ABI by modifying lock_guard
- int128_t has never been standardized because modifying intmax_t is an ABI break. Although if you ask me, intmax_t should just be deprecated.
- unique_ptr could fit in register with language modifications, which would be needed to make it zero-overhead, compared to a pointer
- Many changes to error_code were rejected because they would break ABI
- status_code raised ABI concerns
- A proposal to add a filter to recursive_directory_iterator was rejected because it was an ABI break
- A proposal to make most of <cstring> constexpr (including strlen) will probably die because it would be an ABI break.
- Adding UTF-8 support to regex is an ABI break
- Adding support for realloc or returning the allocated size is an ABI break for polymorphic allocators
- Making destructors implicitly virtual in polymorphic classes
- Return type of push_back could be improved with an ABI break
- Improving shared_ptr would be an ABI break
- [[no_unique_address]] could be inferred by the compiler should we not care at all about ABI
Source: https://cor3ntin.github.io/posts/abi/
alt Hacker News
Being able to change things. It's like all downsides of backwards compatibility but on a binary level
As to things ABI prevents:
- scoped_lock was added to not break ABI by modifying lock_guard
- int128_t has never been standardized because modifying intmax_t is an ABI break. Although if you ask me, intmax_t should just be deprecated.
- unique_ptr could fit in register with language modifications, which would be needed to make it zero-overhead, compared to a pointer
- Many changes to error_code were rejected because they would break ABI
- status_code raised ABI concerns
- A proposal to add a filter to recursive_directory_iterator was rejected because it was an ABI break
- A proposal to make most of <cstring> constexpr (including strlen) will probably die because it would be an ABI break.
- Adding UTF-8 support to regex is an ABI break
- Adding support for realloc or returning the allocated size is an ABI break for polymorphic allocators
- Making destructors implicitly virtual in polymorphic classes
- Return type of push_back could be improved with an ABI break
- Improving shared_ptr would be an ABI break
- [[no_unique_address]] could be inferred by the compiler should we not care at all about ABI
Source: https://cor3ntin.github.io/posts/abi/