I'm trying to understand this concept. Is
Is the keyword thread_localthread_local or '__declspec( thread )'__declspec(thread) a must? In
In the sample of https://learn.microsoft.com/en-us/windows/win32/procthread/using-thread-local-storageUsing Thread Local Storage
on MSDN, why is the variable dwTlsIndex isdwTlsIndex not decorated with 'thread_local'thread_local or '__declspec( thread )'__declspec(thread)?