it's a bit early in the morning for me, but doesn't the change from `unsigned long long` to `unsigned long` mean that by the time you test the result it can't be too large because you've already truncated?
On Sat, Oct 7, 2023 at 11:39 PM Rob Landley <r...@landley.net> wrote: > > On 10/6/23 14:59, enh wrote: > > On Fri, Oct 6, 2023 at 12:35 PM Michael Shavit via Toybox > > <toybox@lists.landley.net> wrote: > >> > >> On Fri, Oct 6, 2023 at 4:41 AM Rob Landley <r...@landley.net> wrote: > >> > > >> > I could adjust _just_ addr to use unsigned long instead of unsigned long > >> > long, > >> > but I don't want two atollu()/atolu() and letting you do a longer > >> > address and > >> > silently truncating it isn't great either. Also, a 32-bit platform can't > >> > do an > >> > atomic 64 bit read/write either (it's gonna do 2 32 bit ones behind the > >> > scenes) > >> > and I kinda don't want to claim it won't? Which means removing the 8 > >> > byte option > >> > when building for 32 bits, which is trivial to do in the code: > >> > > >> > + else if (sizeof(long)==8 && bytes==8) *(unsigned long *)p = data; > >> > >> > >> We can also emit an error earlier in the function if the WIDTH > >> parameter is 8 on a 32 bit platform. > > > >> IMO disallowing 64bit writes is less risky of headaches than silently > >> non-atomic behavior. A clear error message might help alleviate the > >> documentation issue, but I'll agree it's less than ideal to find out > >> that something won't work after the fact. > > > > eh, i actually _prefer_ the error message option --- if someone tries > > this on a 32-bit device, they're probably confused enough that an > > error message will be helpful. whereas seeing nothing in the --help > > text is unlikely to teach them anything. > > > > (bruce tognazzini used to argue against graying out menu items/buttons > > in guis for similar reasons --- "how can you teach the user what > > they've done wrong in that case?". i've never been annoyed by an > > explanation of what i'm doing wrong, but i've often been annoyed by a > > button i can't click and don't understand why!) > > Let me know how commit 5f153b56214f works? I don't have a test environment for > this, but it seems to produce the errors right on 32 and 64 bit at least... > > Rob _______________________________________________ Toybox mailing list Toybox@lists.landley.net http://lists.landley.net/listinfo.cgi/toybox-landley.net
