Problems with the shared_ptr thread safety on g++/mingw

From: Peter Dimov (pdimov_at_[hidden])
Date: 2002-02-16 13:59:26

I have added two more shared_ptr tests in libs/smart_ptr.

shared_ptr_timing_test.cpp can be used to evaluate the performance of the
thread safe implementation relative to the single-threaded baseline
(-DBOOST_DISABLE_THREADS disables shared_ptr thread safety.)

shared_ptr_mt_test.cpp tests the thread safety. Currently it passes for me
on MSVC 7 and Borland 5.5.1 on Windows and g++ 2.96 on Linux (both machines
have a single processor, though.) Unfortunately I get strange errors with
g++/mingw on Windows; when I force shared_ptr to use a CRITICAL_SECTION
via -DBOOST_LWM_WIN32_USE_CRITICAL_SECTION, the problems go away, leading me
to think that the InterlockedExchange "optimized" mutex is either a bit
overoptimized, or I've done something wrong.

Any insights, or results from multiprocessor machines or different
compilers, are appreciated.

--
Peter Dimov
Multi Media Ltd.