On 01/12/2022 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. Well, at least it is in the standard. Although now we have yet another function name doing similar. Might have been simpler to add explicit_bzero to the standard. I can see this has been discussed for two decades https://gcc.gnu.org/bugzilla/show_bug.cgi?id=8537 So it will be like this: void *memset_explicit(void *s, int c, size_t n); I imagine it won't check the pointer is non-NULL. memset_s did do that. Seems pointless to return the pointer. Hopefully no one will use these other variations people have implemented with different parameter types. https://github.com/gsbabil/memset_explicit/blob/master/memset_explicit.h >> >> There are quite a few similar ones that should be easy to add based on existing >> (memcpy_s, memmove_s, strcpy_s, strncpy_s, strcat_s, strncat_s, strtok_s, memset_s, strerror_s, strerrorlen_s, strnlen_s). > > They're not good APIs. See > https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1967.htm and > https://sourceware.org/legacy-ml/libc-help/2018-01/msg00007.html Yes, I know there is a lot of disapproval of Annex K. although I don't feel those trivial memset_s style are. I liked them as they check for non-NULL and return a handy error code. Regards, Jonny
