On Thu, 1 Dec 2022 at 11:31, Jonathan Wakely wrote: > > On Thu, 1 Dec 2022 at 10:44, Jonny Grant wrote: > > Thank you Jonathan and David for your replies. > > > > That "noipa" looks to have sorted this issue > > > > https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html > > > > That page also suggests "noinline" attribute which seems to suggest I'd need to add asm (""); in each wrapper of memset() > > I already used the noinline attribute in my example above. > > > I'd much rather have memset_s - Jonathan, do you think GCC could add some built-in functions for memset_s ? __builtin_memset_s() would be great. > > No. > > But C2x adds a memset_explicit function that does what you want, so > that should arrive in glibc soonish. > I thought it had been added, but was searching the C2x draft for > "memset_secure" and other incorrect names. > > https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2631.htm was the > proposal adding it. Ah, and that proposal links to an example implementation which uses glibc's explicit_bzero which already exists (since glibc 2.25, and also in some BSDs) and does what you want. https://github.com/ojeda/secure_clear/blob/master/example-implementation/secure_clear.h
