[FFmpeg-devel] [PATCH 1/3] configure: use c++11 and fallback to c++0x for c++ files

Marton Balint cus at passwd.hu
Tue Mar 28 23:33:55 EEST 2017


On Sun, 26 Mar 2017, James Almer wrote:

> On 3/26/2017 7:22 AM, Marton Balint wrote:
>> 
>> On Sat, 25 Mar 2017, James Almer wrote:
>> 
>>> On 3/25/2017 8:51 PM, Marton Balint wrote:
>>>> Needed for the C+11 atomics. Also change add_cxxflags to check_cxxflags.
>>>>
>>>> Signed-off-by: Marton Balint <cus at passwd.hu>
>>>> ---
>>>>  configure | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/configure b/configure
>>>> index c1aeb6e..6823894 100755
>>>> --- a/configure
>>>> +++ b/configure
>>>> @@ -4648,7 +4648,7 @@ fi
>>>>
>>>>  add_cppflags -D_ISOC99_SOURCE
>>>>  add_cxxflags -D__STDC_CONSTANT_MACROS
>>>> -add_cxxflags -std=c++98
>>>> +check_cxxflags -std=c++11 || check_cxxflags -std=c++0x
>>>
>>> Do compilers that support setting --std=c++0x (Old provisional name for C++11)
>>> have actual support for std::atomic? They have by definition experimental and
>>> incomplete support for the standard in question.
>> 
>> Yes, gcc supports it since 4.4.
>> https://gcc.gnu.org/projects/cxx-status.html
>> 
>> Also MSVC 2012 (which AFAIK does not even support -std) has support for it:
>> https://msdn.microsoft.com/en-us/library/hh874894(v=vs.110).aspx
>> 
>> Clang since 3.1:
>> https://clang.llvm.org/cxx_status.html
>
> Ok, cool then.
>
>> 
>>> Maybe an actual check for it would be needed if --std=c++11 isn't available.
>> 
>> Well, only decklink_enc needs this, so if we really want to check this, and fail, if not, then it should be done somewhere after checking for decklink stuff. I don't particularly think that is very useful, but can do it if you think so.
>
> No, it's ok. Patch LGTM as is.
>

Ok, thanks, I pushed the series.

Regards,
Marton


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