From: Phillip Wood Date: Sat, 29 May 2021 17:23:20 GMT Subject: Re: [PATCH 1/2] [GSOC] ref-filter: add %(raw) atom Message-ID: In-Reply-To: <60b25ca7a01c2_265088208af@natae.notmuch> On 29/05/2021 16:24, Felipe Contreras wrote: > Phillip Wood wrote: >> On 27/05/2021 17:36, Felipe Contreras wrote: >>> ZheNing Hu via GitGitGadget wrote: >>> [...] >>>> +static int memcasecmp(const void *vs1, const void *vs2, size_t n) >>> >>> Why void *? We can delcare as char *. >> >> If you look at how this function is used you'll see >> int (*cmp_fn)(const void *, const void *, size_t); >> cmp_fn = s->sort_flags & REF_SORTING_ICASE >> ? memcasecmp : memcmp; > > Yeah, but why? > > We know we are comparing two char *. Presumably the reason is that > memcmp and memcasecmp use void *, but that could be remedied with: > > cmp_fn = (int (*)(const char *, const char *, size_t))memcmp; > > That way the same cmp_fn could be used for the two cases. But that is still undefined behavior - the ugly cast just silences any compiler warning without making the code safe. It calls memcmp using a pointer of a different type. The type of cmp_fn and the two functions assigned to it must match. Best Wishes Phillip > Either way I don't care particularly much. It also could be possible to > use void * and do the casting in tolower(). > >>> (and I personally prefer lower to upper) >> >> We should be using tolower() as that is what POSIX specifies for >> strcasecmp() [1] which we are trying to emulate and there are cases[2] where >> (tolower(c1) == tolower(c2)) != (toupper(c1) == toupper(c2)) > > That's true. >