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Re: [PATCH 08/12] Use clock_gettime to implement gettimeofday.
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Zack Weinberg <zackw at panix dot com>
- Cc: <libc-alpha at sourceware dot org>, Florian Weimer <fweimer at redhat dot com>, Lukasz Majewski <lukma at denx dot de>, Alistair Francis <alistair23 at gmail dot com>, Stepan Golosunov <stepan at golosunov dot pp dot ru>, Arnd Bergmann <arnd at arndb dot de>
- Date: Tue, 20 Aug 2019 15:24:21 +0000
- Subject: Re: [PATCH 08/12] Use clock_gettime to implement gettimeofday.
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- References: <20190820132152.24100-1-zackw@panix.com> <20190820132152.24100-9-zackw@panix.com>
On Tue, 20 Aug 2019, Zack Weinberg wrote:
> __gettimeofday is no longer called by anyone, so remove its internal
> prototype and its entries in Versions and .abilist files. (It would
> have been a GLIBC_PRIVATE symbol if the GLIBC_PRIVATE convention had
> been invented back in the days of 2.0.)
That's not obviously safe. The choice of which internal symbols to move
to GLIBC_PRIVATE when GLIBC_PRIVATE was introduced
2002-02-01 Jakub Jelinek <jakub@redhat.com>
* Versions.def (libc): Add GLIBC_PRIVATE.
[...]
was clearly a deliberate choice (as was the choice of which symbols in
glibc 2.0 not to export at a public symbol version when symbol versioning
was introduced in 2.1). __gettimeofday is certainly the kind of symbol
that could have been used by a library with its own namespace concerns
(cf. past discussions of how we might enable libstdc++ to be
namespace-clean), although maybe more likely to have been used by an
application that should be using gettimeofday.
Perhaps someone set up to do so could check large sets of current and past
distribution binaries for any reference to the __gettimeofday symbol in
executable / shared library dynamic symbol tables, as evidence for whether
such an ABI change is safe or not?
--
Joseph S. Myers
joseph@codesourcery.com