[openssl-dev] [openssl-team] Discussion: design issue: async and -lpthread

[Florian Weimer]

On 11/25/2015 06:48 PM, Kurt Roeckx wrote:
> On Wed, Nov 25, 2015 at 01:02:29PM +0100, Florian Weimer wrote:
>> On 11/23/2015 11:08 PM, Kurt Roeckx wrote:
>>
>>> I think that we currently don't do any compile / link test to
>>> detect features but that we instead explicitly say so for each
>>> platform.
>>>
>>> Anyway, the gcc the documentation is here:
>>> https://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html
>>>
>>> TLS support clearly isn't supported everywhere.
>>
>> The most portable approach is to switch C++11, which provides you
>> thread-local variables with destructors (and you also get portable
>> atomics).  There are simply no standards-based C solutions as long as
>> you have to support the Microsoft compiler under Windows.
> 
> Please note that we use C, not C++.  But C11 has the same atomics
> extentions as C++11.

C++11 support is much more widespread than C11 support.  You will have
trouble finding reliable support for C11 atomics with the Microsoft
toolchain.

> We're also currently still targetting C89/C90 (with some minor
> extentions), but I think we should try to use them if the platform
> supports it.

It is a lot of working getting the atomics right on all supported platforms.

Florian