Hi Paul, On 1/5/23 21:55, Paul Eggert wrote:
On 2023-01-05 12:48, Adhemerval Zanella Netto via Libc-alpha wrote:On 05/01/23 16:37, Alejandro Colomar via Libc-alpha wrote:bzero(3) is simpler to use, and can avoid silly mistakes that are hard to spot. memset(3), while it is necessary in a few very-specific cases, should be avoided when the memory is to be zeroed. POSIX and ISO can say otherwise, but it doesn't make any sense to recommend using memset(3) over bzero(3).bzero is deprecated by POSIX.1-2001, removed by POSIX.1-2008, and on glibc implementation now calls memset (previously some architecture added ifunc redirection to optimized bzero to avoid the extra function call, it was removed from all architectures). Also, GCC for some time also replaces bzero with memset so there is no gainin actually call bzero (check glibc commit 9403b71ae97e3f1a91c796ddcbb4e6f044434734).In addition, gcc -Wall warns if you mistakenly pass 0 as memset's 3rd arg, which undercuts the argument that bzero avoids silly mistakes.
That's a good counterargument for the silly mistakes point. But the cognitive load that programmers need to care about the extra useless argument for no good reason is still a problem of the memset(3) API that bszero(3) simply hasn't.
If it's about defending a minimal set of functions that serve the basic purposes that programmer may need, I'll prepare a counterargument:
Why does POSIX have strnlen(3)? strnlen(s, n) is just a shorthand for memchr(s, '\0', n);
If the similarity wasn't obvious enough, I'll put them together: strnlen(p, n) ---- memchr(p, 0, n) bzero(p, n) ---- memset(p, 0, n)I'd like to get a rationale for why we should promote strnlen(3) but not bzero(3) that doesn't reduce to "it is standard". Why would the standard cover on and not the other?
Cheers, Alex
-- <http://www.alejandro-colomar.es/>
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