See this glibc bug: https://sourceware.org/bugzilla/show_bug.cgi?id=18924 This needs mentioning in the section about C, maybe C++ (for std::array), and perhaps in the library API guidelines.
I'm closing this bug as part of a Bugzilla cleanup effort. The most likely reason is that the bug has been opened either against a component we no longer publish, or against Release Notes for an EOL release.