C++0x thread class: library dependency

[hendrixj]

In order to get g++ 4.5 (with -std=c++0x) to launch the new standard thread correctly, I had to link with -lpthread.
I'm running on Linux, btw.
I'm not surprised that g++ used pthreads, but I was surprised that I needed to add the link flag. Is this the expected behavior?
In other words, are we doomed to have to specify the library implementation at link time, or should we expect the language now to do that automagically?

[Danny]

No. that's not the standard behavior. The C++ standard doesn't even recognize pthreads so it certainly won't require that. However, I suspect that the GCC library used pthreads to implement the new threading facilities so it forces you to add that flag. It's remiscent of the early days of <iostream.h> when people had to #include <stdio.h> because the stream library was built upon stdio.