It’s been a while since I post something technical here. We are currently really busy on our new secret project, but I have something to share.

Some compilers have an interesting property : __declspec(thread) for Microsoft cl.exe, __thread for Gcc. By using this declaration on a global variable, a copy of the variable is created for each thread. This is known as a Thread Local Storage (TLS). You can always use direct calls to the system’s API ( TLSGetValue and TLSSetValue for Windows, pthread_getspecific and pthread_setspecific for POSIX systems), but using automatic TLS variable is very comfy. As you may know, Mojito is available on several platforms, some of them does not provide those kind of variables. And if provided, those variables are limited to POD (Plain Ol’ data) variables. So we search for a solution that is close to what compiler can offer.

(more…)