Re: [PATCH] c++: Predefine __STDCPP_THREADS__ in the compiler if thread model is not single

[Jeff Law <law@redhat.com>]

On 11/13/20 10:29 AM, Jakub Jelinek via Gcc-patches wrote:
> Hi!
>
> The following patch predefines __STDCPP_THREADS__ macro to 1 if c++11 or
> later and thread model (e.g. printed by gcc -v) is not single.
> There are two targets not handled by this patch, those that define
> THREAD_MODEL_SPEC.  In one case - QNX - it looks just like a mistake
> to me, instead of setting thread_model=posix in config.gcc it uses
> THREAD_MODEL_SPEC macro to set it unconditionally to posix.
> The other is hpux10, which uses -threads option to decide if threads
> are enabled or not, but that option isn't really passed to the compiler.
> I think that is something that really should be solved in config/pa/
> instead, e.g. in the config/xxx/xxx-c.c targets usually set their own
> predefined macros and it could handle this, and either pass the option
> also to the compiler, or say predefine __STDCPP_THREADS__ if _DCE_THREADS
> macro is defined already (or -D_DCE_THREADS found on the command line),
> or whatever else.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 
>
> 2020-11-13  Jakub Jelinek  <jakub@redhat.com>
>
> 	* c-cppbuiltin.c: Include configargs.h.
> 	(c_cpp_builtins): For C++11 and later if THREAD_MODEL_SPEC is not
> 	defined, predefine __STDCPP_THREADS__ to 1 unless thread_model is
> 	"single".

OK.  Note that hpux10 should be considered long dead.   I wouldn't let
that get in the way of anything.  One could argue we should remove
hpux10 and earlier, leaving just hpux11.


Jeff