* Alan Coopersmith: > On 7/26/24 12:46, Solar Designer wrote: >> Unfortunately, *asprintf() are not that easy to use safely: >> "For asprintf(), if memory allocation was not possible, or if some >> other >> error occurs, the function shall return a negative value, and the >> contents of the location referenced by ptr are undefined, but shall not >> refer to allocated memory." > [...] >> As I recall, on *BSD's *asprintf() also reset the pointer to NULL. On >> upstream glibc, it does not. We failed to get this change past Ulrich >> back then: >> https://sourceware.org/legacy-ml/libc-alpha/2001-12/msg00045.html > > Yes, this came up in the discussion to add asprintf() to POSIX in > https://austingroupbugs.net/view.php?id=1496 : > >> Of the above listed implementations, all but GNU libc document that they will >> set *ptr to NULL on error, while GNU libc explicitly states that you cannot >> rely on it to do so (and looking at its code, sometimes it does, sometimes >> it doesn't). > > and so the standard was written to allow both ways to be conformant. > > If GNU libc was willing to change that, perhaps the next version of the > standard could as well.
I submitted a glibc patch: [PATCH] libio: asprintf should write NULL upon failure <https://inbox.sourceware.org/libc-alpha/87zfq0r8aj....@oldenburg.str.redhat.com/> Thanks, Florian
