In single-threaded processes, the size of the stack is usually limited only by the amount of free memory space because the stack can continue to grow until it runs into the memory space allocated for the heap.

In a multithreaded application, each thread’s stack must be limited because each thread has its own stack, and every thread stack must be allocated in the same address space. To allocate a stack, each thread must reserve some fixed-sized portion of the address space. The growth of these stacks is now limited by their allocation size and the presence of other thread stacks in the same address space. Stack allocation is demonstrated in Figure 20.