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Re: _GLIBCXX_PROFILE on non-Linux?
On Tue, Jan 19, 2010 at 7:23 AM, Paolo Carlini <paolo.carlini@oracle.com> wrote:
>
> On 01/19/2010 04:20 PM, Ian Lance Taylor wrote:
> > You can diagnose it at compile time via something like
> >
> > #ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
> >
> Eh, the macros I implemented a while ago turn out to be useful ;)
>
> Sure, anyway, I agree with Ian, Silvius could add something like this...
>
> Paolo.
Will do ASAP.
There is also a profile mode specific _GLIBCXX_PROFILE_NO_THREADS that
users can turn on to guarantee that programs are single-threaded.
When it's defined, profile mode pthread lock/unlock operations become
nops. Unfortunately, the atomic operations are not guarded by it
currently. I should perhaps add preprocessor conditionals to avoid
all calls to atomic builtins when _GLIBCXX_PROFILE_NO_THREADS is
defined. That way, at least sequential programs will work regardless
of builtin support in the compiler. Something like:
#ifdef _GLIBCXX_PROFILE_NO_THREADS
x = x + 1;
#else
__sync_fetch_and_add(&x, 1);
#endif
Thank you all for coming up with the report, diagnostic, plus the solution!
Silvius