This routine obtains the value of the stack address attribute of
the thread attributes object specified in the attr argument and
stores it in the location specified by the stackaddr argument.
The specified attributes object must already be initialized when
this routine is called.
The stack address attribute of a thread attributes object points
to the origin of the stack for a new thread.
Note that the value of the stack address attribute of a
particular thread attributes object does not necessarily
correspond to the actual stack origin of any existing thread
in your multithreaded program.