Why is there a difference using std::thread::hardware_concurrency() and boost::thread::hardware_concurrency()?

Question

The description of the problem itself is pretty simple. I\'m testing the differences of std::thread library in C++11 and boost::thread library.

The output of these:

Answer 1

After reviewing /usr/include/c++/4.6.2/thread

it can be seen that the implementation is actually:

// Returns a value that hints at the number of hardware thread contexts.
static unsigned int
hardware_concurrency()
{ return 0; }

So problem solved. It's just another feature that hasn't been implemented in gcc 4.6.2