We only build MyRocks on gcc 4.8+, clang 3.3+, or MSVC 19.0+ ( cf. https://github.com/MariaDB/server/blob/10.4/storage/rocksdb/CMakeLists.txt#L51)
all of which have thread_local support, as per https://en.cppreference.com/w/cpp/compiler_support To me it seems like safe to use C++11 feature, in MyRocks From: Eugene Kosov Sent: Tuesday, November 27, 2018 9:44 PM To: Sergey Petrunia; maria-developers Cc: Vicențiu Ciorbaru; Vladislav Vaintroub Subject: Re: [Maria-developers] Do we support compilers that support C++11 butnot thread_local? Hi. This page may be useful for you https://en.cppreference.com/w/cpp/compiler_support It says that until gcc 4.8 support is partial. And I can see a buildbot for 10.4 with gcc 4.4.6 http://buildbot.askmonty.org/buildbot/builders/kvm-bintar-centos6-x86/builds/392/steps/compile/logs/stdio 27.11.2018, 23:07, "Sergey Petrunia" <ser...@mariadb.com>: > Hi, > > I'm writing this in connection with MyRocks Storage Engine and > https://github.com/facebook/mysql-5.6/issues/904 > > C++ 11 includes "thread_local" specifier : > https://en.cppreference.com/w/cpp/keyword/thread_local > > GNU also has __thread, which was available before C++11. > > RocksDB (and so MyRocks) uses both __thread and thread_local. thread_local is > part of the standard, so they might switch to thread_local. > The question: will it cause any issues for us? > > In other words, do we have compilers/environments that > - claim to support C++11 (so that we attempt to compile MyRocks) > - but do not support "thread_local" > ? > > For Windows, RocksDB does this in port/win/port_win.h: > > #ifndef __thread > #define __thread __declspec(thread) > #endif > > but this page page about Visual Studio 2015) > https://msdn.microsoft.com/en-us/library/6yh4a9k1.aspx > > says that > > C++11: The thread_local storage class specifier is the recommended > way to specify thread-local storage for objects and class members. > > I assume this means it's ok to use thread_local on Windows? > > RocksDB source code mentions one problematic case: > > // However, thread_local is not supported in all compilers that accept > -std=c++11 > // (e.g., eg Mac with XCode < 8. XCode 8+ supports thread_local). > > As far as I understand this is not relevant for us? > > Anyone aware of other such cases? > > BR > Sergei > -- > Sergei Petrunia, Software Developer > MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog > > _______________________________________________ > Mailing list: https://launchpad.net/~maria-developers > Post to : maria-developers@lists.launchpad.net > Unsubscribe : https://launchpad.net/~maria-developers > More help : https://help.launchpad.net/ListHelp -- Eugene
_______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
