The problem(difference) in the gnu website about C++11 support in a specific version of GCC

The problem(difference) in the gnu website about C++11 support in a specific version of GCC

[Qiye Tan]

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Dear GCC Helper:



I have found that in website:
https://gcc.gnu.org/projects/cxx-status.html#cxx11, the Table Concurrency
shows that GCC 4.3 support the proposal N2660, however, when I went to GCC
4.3 c++0x status website (https://gcc.gnu.org/gcc-4.3/cxx0x_status.html)
for detail information, I found that it shows that GCC 4.3 doesn’t support
proposal N2660. What’s more, I don’t know why my gcc doesn’t have the
predefine MACRO “__cpp_threadsafe_static_init”, it even doesn’t have the
MACRO “__cpp_rtti”. So, can you tell me that whether threadsafe_static_init
is supported in GCC 4.3? Thank you so much!



Here is the screenshot of
https://gcc.gnu.org/projects/cxx-status.html#cxx11
[image: gcc1.PNG]

And the screenshot of https://gcc.gnu.org/gcc-4.3/cxx0x_status.html
[image: gcc2.PNG]



Best Regards,

Qiye Tan

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Re: The problem(difference) in the gnu website about C++11 support in a specific version of GCC

[Jonathan Wakely]

On Mon, 13 Apr 2020 at 06:22, Qiye Tan via Gcc-help
<gcc-help@gcc.gnu.org> wrote:
>
> Dear GCC Helper:
>
>
>
> I have found that in website:
> https://gcc.gnu.org/projects/cxx-status.html#cxx11, the Table Concurrency
> shows that GCC 4.3 support the proposal N2660, however, when I went to GCC
> 4.3 c++0x status website (https://gcc.gnu.org/gcc-4.3/cxx0x_status.html)
> for detail information, I found that it shows that GCC 4.3 doesn’t support
> proposal N2660.

It's likely the gcc-4.3 docs were not updated at the time, and so are incorrect.

> What’s more, I don’t know why my gcc doesn’t have the
> predefine MACRO “__cpp_threadsafe_static_init”, it even doesn’t have the
> MACRO “__cpp_rtti”.

GCC 4.3.6 was released in 2011.

The initial proposal for the idea of standardized macros was published in 2012:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3435.htm
The first "__cpp_xxx" macros were proposed in 2013:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3694.htm
But the __cpp_rtti macro wasn't proposed until much later:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4200.htm
And the __cpp_threadsafe_static_init macro even later:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0096r5.html

It's completely unsurprising that a compiler released in 2011 doesn't
implement a feature invented several years later.


> So, can you tell me that whether threadsafe_static_init
> is supported in GCC 4.3? Thank you so much!

The -fno-threadsafe-statics option is documented in the GCC 4.3
manual, so yes, it's supported.