Glibc compatibility

[Florian Weimer]

* Suresh Kachwa:

> Please see below and help us with one question: Is it safe to update glibc when the binaries are
> compiled with a lower version of glibc?
>
> Oracle Linux 9:
> glibc is available by default:
> Before running "yum update", glibc version is 2.34
> After running "yum update", glibc version is 2.34
> Oracle Linux 8:
> glibc is available by default:
> Before running "yum update", glibc version is 2.28
> After running "yum update", glibc version is 2.28
> Oracle Linux 7.9:
> glibc is available by default:
> Before running "yum update", glibc version is 2.17
> After running "yum update", glibc version is 2.17
> Oracle Linux 6.10:
> glibc is available by default:
> Before running "yum update", glibc version is 2.12
> After running "yum update", glibc version is 2.12

Shouldn't this question be directed at Oracle, given that you are using
Oracle Linux?

For upstream glibc, we try to provide backwards compatibility, but doing
so may conflict with other goals (managing implementation complexity,
security hardening).  We do not aim for bug-for-bug compatibility:
behavior that is outside the specfication can change.  An example is
that the precise return value of the memcmp function for particular
input strings (and not just the sign of the return value).

Does this answer your question?

Thanks,
Florian