Re: [boost] Re: shared_ptr: unsafe, or am I crazy?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2002-01-20 10:23:24

From: "Larry Evans" <jcampbell3_at_[hidden]>
> > I am using Peter's
http://groups.yahoo.com/group/boost/files/smart_ptr_3.zip.
> > I've tried using gdb to trace and see what's happening, but it's
skipping some
> > lines of code (I guess because of optimizing).  Anyway, here's the
output:
>
> Probably only the implementors would be interested in the details below.
>
> Update:  used -fno-default-inline oncompiler and traced the problem to
> a work-around to no atomic.h with my compiler.  I simply created my own
> atomic.h as follows:
>
>    #define ATOMIC_INIT(X) X
>   typedef long atomic_t;
>   static void atomic_inc(atomic_t*a_val){++*a_val;}
>   static long atomic_dec_and_test(atomic_t*a_val){return --*a_val;}
>   static long atomic_read(atomic_t const*a_val){return *a_val;}

According to

http://kernelnewbies.org/documents/kdoc/kernel-api/r287.html

atomic_dec_and_test should return --*a_val == 0;

BTW I thought that atomic.h was required to be present on Linux? It's in
/usr/include/asm/atomic.h on my system.

BTW2 You can #define BOOST_DISABLE_THREADS to make atomic_count be a simple
long.

--
Peter Dimov
Multi Media Ltd.