This routine sets the stacksize attribute in the thread attributes object specified by the attr argument. Use this routine to adjust the size of the writable area of the stack for a new thread. The size of a thread's stack is fixed at the time of thread creation. On OpenVMS systems, only the initial thread can dynamically extend its stack. On Tru64 UNIX systems, very large stacks can be created, but only a few pages are committed. Many compilers do not check for stack overflow. Ensure that the new thread's stack is sufficient for the resources required by routines that are called from the thread.