Hi Nevin, On Wed, Jan 07, 2026 at 08:37:15PM -0600, Nevin Liber wrote: > On Wed, Jan 7, 2026 at 8:31 AM David Svoboda wrote: > > > Here are some more thoughts on n3752 > > [...] > > WRT this text: > > > > Code written for platforms returning a null pointer can be > > migrated to platforms returning non-null, without significant > > issues. > > > > I am very skeptical that this is indeed true. But to be precise, this is > > Glibc's problem rather than WG14's. If they are willing to change glibc to > > return non-null on realloc(0), then I am willing to agree to this change in > > ISO C. > > > > Is there any evidence that changing this behavior breaks no code? Any > > test failures? Any surveys? > > > > And if it breaks no code, is that because this is a corner case that > doesn't occur in practice? It's not because of a corner case. It's because if it would go wrong, the worst that can happen is a memory leak of 0 bytes plus metadata (~16 B, usually). And yes, it's a corner case, so it's not like you'll be leaking those 16 B regularly. > That in itself doesn't mean we shouldn't change it. The reason to change it is that with the current specification and implementation you can get serious vulnerabilities: remote code execution. Also, that programming will be much easier if all implementations behave in the most simple way. > > This paper ignores Windows other than to mention that it would need to > > change too. I doubt MS will update MSVC to accommodate this paper. So > > accepting this paper makes MSVC noncompliant. > > > > This is the part that is troublesome to me. What is the point of changing > this behavior if two (or even just one) major implementations are going to > ignore it? Do you know anyone from MS in WG21? It would be great to talk to them. Have a lovely day! Alex --