libthr shared locks

Julian Elischer julian at
Sat Dec 26 02:46:57 UTC 2015

On 24/12/2015 1:25 AM, Konstantin Belousov wrote:
> A well-known limitation of the FreeBSD libthr implementation of the
> pthread locking objects is the missed support for the process-shared
> locks.  The hardest part of implementing the support is the neccessity
> of providing ABI compatibility for the current implementation.

> [...]

> Changing this ABI is very hard.  libthr provides the symbol
> versioning, which allows to provide compatible shims for the previous
> ABI variant.  But since userspace tends to use the pthread objects in
> the layouts of the library objects, this causes serious ABI issues
> when mixing libraries built against different default versions of
> libthr.

which is one reason I think symbol versioning is over-rated..
just make a new library version.

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