https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99770
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Nishant Chauhan from comment #0) > Is this a bug in gcc on arm? No, the warning is correct. You are passing NULL where a size_t is expected. That's probably a bug in your code, you should fix it. I get a warning on x86_64-linux with GCC 7.5 (and with all later versions).