Varying filesize of libstdc++.so.6.0.19

[Mohan Ganesalingam]

Thank you very much !
On Tue, 29 May 2018 at 15:56, Jonathan Wakely <jwakely@redhat.com> wrote:

> On 24/05/18 21:58 +0100, Mohan Ganesalingam wrote:
> >Thanks very much for the quick reply!
> >
> >We think we have figured out some things about portability (of a library
> >that links with libstdc++  *and no other libraries*) by testing – could I
> >ask and see if they are reliably true?
> >
> >1. If the library dynamically links with, say, libstdc++.so.6.0.19, then
> it
> >can be compiled on one distro/version and used on another so long as
> >libstdc++.so.6.0.19 or newer (and the requisite glibc) is present.
> >
> >2. A compiled libstdc++.so.6.0.19 from one distro/version can be used on
> >another distro/version. This means that if the library is statically
> linked
> >against libstdc++ 6.0.19 on one distro/version, it will again work on
> >other distro/versions
> >as long as the right glibc is present.
> >
> >These seem to hold across (some version of) CentOS, Ubuntu, Fedora.
> >
> >NB. The library doesn't do anything that would explicitly make it OS
> >-dependent – so it doesn't try to open system files, call 'system', access
> >specific devices, etc..
> >
> >Is there a table somewhere that lists what minimum version of libc is
> >required for each version of libstdc++?  (Similar to the tables in
> >https://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html )
>
> There is no minimum libc required for each version of libstdc++.
> Anything newer than glibc 2.3 can be used, but an older glibc might
> result in some features in libstdc++ being disabled.
>
> The dependencies on glibc come from the glibc version that libstdc++
> was built against. In other words the dependency depends how libstdc++
> was built, not on the version of libstdc++ you use. That can vary
> between OS distros, because two distros might use the same GCC release
> but built against different glibc releases. That would mean their
> libstdc++.so libraries have different dependencies on glibc.
>
>
>