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Subject: [boost] Boost.Xint is not thread-safe
From: Bryce Lelbach (blelbach_at_[hidden])
Date: 2011-06-19 13:29:41

The proposed Boost.Xint does not fulfill the thread-safety promises that it
makes. The library uses a custom allocator (allocator_t), which uses global
variables and does not protect them with a synchronization primitive. There
appears to be no way to override the use of this custom allocator (the library
just passes the user-specified STL allocator to allocator_t, and allocator_t
uses the STL allocator to get memory).

Can the author of this library please make the custom allocation strategy
optional? Merely making allocator_t threadsafe wouldn't be a solution for me
unless I could change the synchronization primitive that this allocator uses.
I am using this library within a parallel C++ runtime that implements (among
other things) a user-threading layer, so I would want to use one of our
synchronization primitives, as OS-level (e.g. Boost.Thread) based synchronization
would interfere with our user threading subsystem.

I think the better solution here is to not tie Boost.Xint to a particular memory
allocation scheme.

The allocator in question is in <boost/xint/detail/policies.hpp>

Bryce Lelbach aka wash

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