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Re: (ITS#9069) Stop setting custom GnuTLS mutex functions

Ryan Tandy wrote:
> On Wed, Aug 28, 2019 at 01:34:31PM +0100, Howard Chu wrote:
>> This is not a safe assumption on Windows, unfortunately. While libldap uses native
>> Windows mutexes on Windows, a lot of code built using gcc/g++ uses a posixthreads
>> emulation library for thread and mutex support, and the user-visible structures are
>> not compatible with native mutexes. (I've found this to be a significant problem
>> for g++ std::mutex, std::thread, etc.)
> 
> Thanks for mentioning that. GnuTLS also uses native Windows threads when building for Windows (including mingw-ish environments), so it should still be OK; but
> I'd better go and figure out a smoke test on Windows too.
> 
> How does this work on the OpenSSL side? For 1.1.0+ it sounds like the same situation, with OpenSSL using the Windows native API as well.
> 
> Does "incompatible" just mean that a single mutex object can't be shared between the two APIs? (I don't think that would be an issue for our case.) Or is it
> something stronger like a pthreads mutex not being able to synchronize native threads, or outright not being able to use both interfaces in a single process?
> 
Passing a native structure to the posixthreads interface (and vice versa) will crash the program (or
worse - silently corrupt memory without crashing the program....)

-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/