From: Joseph Myers <joseph@codesourcery.com>
To: Lukasz Majewski <lukma@denx.de>
Cc: <libc-help@sourceware.org>, Florian Weimer <fweimer@redhat.com>,
Adhemerval Zanella <adhemerval.zanella@linaro.org>
Subject: Re: Question regarding __clock_gettime symbol visibility across glibc build
Date: Mon, 23 Mar 2020 21:57:52 +0000 [thread overview]
Message-ID: <alpine.DEB.2.21.2003232154040.13609@digraph.polyomino.org.uk> (raw)
In-Reply-To: <20200321080040.7ac91d19@jawa>
On Sat, 21 Mar 2020, Lukasz Majewski wrote:
> > /work/lukma/glibc/glibc-many-build/src/glibc/malloc/memusage.c:181:
> > undefined reference to `__clock_gettime64'
I.e. __clock_gettime64 is not exported at any symbol version in the
dynamic symbol table of libc.so.
Any symbol defined in libc.so and used in another glibc shared library or
executable needs to be exported at some symbol version in some Versions
file. In the case of symbols for 64-bit time, it should be exported at
version GLIBC_PRIVATE until we're ready to support _TIME_BITS=64 in the
headers, at which point all such symbols should be exported at the version
of the next glibc release and be removed from GLIBC_PRIVATE if there.
> > nm
> > ./work/glibc/glibc-many-build/build/glibcs/arm-linux-gnueabi/glibc/libc.so
> > | grep clock_gettime
nm uses the static symbol table by default. You need nm -D, objdump -T
(shows symbol versions as well) or readelf --dyn-syms to look at the
dynamic symbol table.
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2020-03-23 21:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-17 7:47 Lukasz Majewski
2020-03-17 8:34 ` Florian Weimer
2020-03-17 8:51 ` Lukasz Majewski
2020-03-21 7:00 ` Lukasz Majewski
2020-03-23 21:57 ` Joseph Myers [this message]
2020-03-23 22:14 ` Lukasz Majewski
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