Hi all, NuttX 13.0.0 will be branched out on 01.06 please merge all breaking changes before the date so that we have time to test the release branch
Best regards Alin On Sun, May 3, 2026 at 9:30 PM Gregory Nutt <[email protected]> wrote: > A simple alternative would be to configure a "bytes per time_t" value and > if that is not not 8, then provide a library function that implements > uint64_t with multiple byte accesses and provides atomic operation. This > would not be so difficult and would eliminate any significant size increase > but would trash performance on low-end microcontrollers. > > ________________________________ > From: Alan C. Assis <[email protected]> > Sent: Sunday, May 3, 2026 10:46 AM > To: [email protected] <[email protected]> > Subject: Re: [DISCUSS] Removal of CONFIG_SYSTEM_TIME64 and make time_t > 64-bit by default > > Yes, that was my point, but "I was outvoted". > > I think making it default will avoid this issue in 99.9% of all devices > (because only people trying to run NuttX on small devices will try to > disable it). > > And if POSIX compatibility is the problem, we could print a WARNING at the > end of compilation saying: your firmware is not POSIX compatible because > you disabled CONFIG_SYSTEM_TIME64. > > I think 2KB+ means we no longer will be able to support boards with less > than 32KB Flash. > > BR, > > Alan > > On Sun, May 3, 2026 at 1:43 PM <[email protected]> wrote: > > > Hello, > > > > I tried for AVR128DA28 - tools/configure.sh -l breadxavr:nsh > > > > Default setting (CONFIG_SYSTEM_TIME64 not set): > > > > Register: nsh > > Register: sh > > LD: nuttx > > Memory region Used Size Region Size %age Used > > flash: 50457 B 128 KB 38.50% > > sram: 636 B 16 KB 3.88% > > eeprom: 0 B 512 B 0.00% > > rodata: 592 B 4 KB 14.45% > > CP: nuttx.hex > > CP: nuttx.asm > > > > With CONFIG_SYSTEM_TIME64 set: > > > > Register: nsh > > Register: sh > > LD: nuttx > > Memory region Used Size Region Size %age Used > > flash: 52307 B 128 KB 39.91% > > sram: 668 B 16 KB 4.08% > > eeprom: 0 B 512 B 0.00% > > rodata: 592 B 4 KB 14.45% > > CP: nuttx.hex > > CP: nuttx.asm > > > > 2kB seems quite noticeable for a chip with 128kB flash. Runtime costs > > are somewhat hard to assess, the time_t type is used in internal > > timekeeping but the code was developed with tickless mode of operation > > in mind so the timekeeping functions should not run that often unless > > the system gets busy with processing lots of timed events. > > > > As for the benefits - the real question is how many devices (designed > > with a chip like this one) need to know real time and therefore handle > > year 2038. (None of my use cases need that.) > > > > So for small systems, having the option to configure NuttX so time_t is > > 32 bit wide would certainly be beneficial. Making the SYSTEM_TIME64 > > option default to DEFAULT_SMALL would be nice but it's not POSIX-correct > > so I don't think that's gonna fly. > > >
