例如:
#include <thread>
thread_local int n = 1;
void f()
{
++n; // is n initialized here for each thread or prior to entering f()?
}
int main()
{
std::thread ta(f);
std::thread tb(f);
ta.join();
tb.join();
}
从这里仍然不完全清楚n何时被初始化。