According to 'man 3 printf' %j appeared in glibc 2.1 and seems to be C99 feature. That's decidedly ancient.
And may I be allowed to suggest, unless elfutils is tested in upstream CI with decade-old toolchains, you should not be considering its compatibility with them. Alex On Thu, 25 Nov 2021 at 18:51, Frank Ch. Eigler <f...@redhat.com> wrote: > Hi - > > > Use intmax_t to print time_t > > [...] > > - if (dprintf(fd, "%ld", cache_config_default_s) < 0) > > + if (dprintf(fd, "%jd", (intmax_t)cache_config_default_s) < 0) > > [...] > > I'm not a compatibility specialist, but note that elfutils is sometimes > built on decade-old toolchains, where use of %lld and (long long) would > certainly work. We have such in the code base already, whereas this would > be the first %j. > > - FChE > >