libboost-atomic1.71-dev 1.71.0-3 (s390x binary) in ubuntu focal

 This package forms part of the Boost C++ Libraries collection.
 .
 Boost.Atomic is a library that provides atomic data types and
 operations on these data types, as well as memory ordering
 constraints required for coordinating multiple threads through atomic
 variables. It implements the interface as defined by the C++11
 standard, but makes this feature available for platforms lacking
 system/compiler support for this particular C++11 feature.
 .
 Users of this library should already be familiar with concurrency in
 general, as well as elementary concepts such as "mutual exclusion".
 .
 The implementation makes use of processor-specific instructions where
 possible (via inline assembler, platform libraries or compiler
 intrinsics), and falls back to "emulating" atomic operations through
 locking.