Issue #20290 has been updated by mdalessio (Mike Dalessio).
Have you got an example of a particular C extension which needs to free memory in this way?
I haven’t looked. But if the C extension does initialization with an external library, then it might need this to release that memory at shutdown.
I would consider calling libxml2's `xmlCleanupParser` from Nokogiri's `Destruct` function if this feature is made available, because libxml2 keeps some long-lived global state (like character encoding handlers) that would not otherwise be freed. ---------------------------------------- Feature #20290: Add API for C extensions to free memory https://bugs.ruby-lang.org/issues/20290#change-106955 * Author: peterzhu2118 (Peter Zhu) * Status: Open ---------------------------------------- GitHub PR: https://github.com/ruby/ruby/pull/10055 Ticket #19993 added the new feature RUBY_FREE_AT_EXIT, which frees memory in Ruby at shutdown. This allowed tools like Valgrind, ASAN, and macOS leaks to find memory leaks in Ruby without a large number of false-positives outputted. However, this feature is not complete for C extensions, as they may also need to free their memory and there was no way to do so. This means that C extensions might not be able to directly use tools like Valgrind, ASAN, or macOS leaks to find memory leaks. This ticket proposes an API for C extensions to free memory by defining a function called `Destruct_<extension name>` that is called during shutdown when RUBY_FREE_AT_EXIT is enabled. This name mirrors the `Init_<extension name>` API that already exists for extension initialization. However, unlike the `Init_<extension name>` function, `Destruct_<extension name>` is NOT mandatory for the C extension to implement so that we can preserve backwards compatibility. -- https://bugs.ruby-lang.org/