Description

   This routine uses the value specified in the stackaddr argument
   to set the stack address attribute of the thread attributes
   object specified in the attr argument.

   When creating a thread, use a thread attributes object to specify
   nondefault values for thread attributes. The stack address
   attribute of a thread attributes object points to the origin
   of the stack for a new thread.

   The default value for the stack address attribute of an
   initialized thread attributes object is NULL.

                                  NOTE

      Correct use of this routine depends upon details of the
      target platform's stack architecture. Thus, this routine
      cannot be used in a portable manner.

      The size of the stack must be at least PTHREAD_STACK_MIN
      bytes (see the pthread.h header file). However, because the
      Threads Library must use a portion of this stack memory to
      begin thread execution and to maintain thread state, your
      program's "user thread code" cannot rely on using all of the
      stack memory allocated.

   For your program to calculate a value for the stackaddr
   attribute, note that:

   o  Your program must allocate the memory that will be used for
      the new thread's stack.

   o  On Tru64 UNIX, to create a new thread using a thread
      attributes object, the stackaddr attribute must be an address
      that points to the high-memory end of the memory region
      allocated for the stack. This address must point to the
      highest even-boundary quadword in the allocated memory region.

   Also note that:

   o  If you use the pthread_attr_setstackaddr() routine to set a
      thread attributes object's stack address attribute and use
      that attributes object to create a new thread, the Threads
      Library ignores the attributes object's guardsize attribute
      and provides no thread stack guard area or overflow warning
      area for the new thread.

   o  If you use the same thread attributes object to create more
      than one thread and each created thread uses a nondefault
      stack address, you must use the pthread_attr_setstackaddr()
      routine to set a unique stack address attribute value for each
      new thread created using that attributes object.