&gt; I don&#x27;t actually expect glibc to break this in the foreseeable future<p>Would you have said this if Ulrich Drepper was still in charge of glibc? Under his ownership glibc broke all sorts of things that happened to rely on memcpy behaving like memmove[1]. I&#x27;m not sure he would have been any more accommodating of non-conforming compilers than of non-conforming flash implementations.<p>[1] <a href="https:&#x2F;&#x2F;sourceware.org&#x2F;bugzilla&#x2F;show_bug.cgi?id=12518" rel="nofollow">https:&#x2F;&#x2F;sourceware.org&#x2F;bugzilla&#x2F;show_bug.cgi?id=12518</a>