c++ - Is stack memory contiguous?

Question

How does the compiler enforce the stack memory to be contiguous, does it cause the memory to be moved everytime while the program is running or does it reserve the memory on stack needed by program before running it?

Answer 1

The stack for a given thread is often contiguous in virtual memory (on Linux and similar systems, and in user mode in Windows). The Windows kernel (in Windows Vista and above) and z/OS allow discontiguous stacks in virtual memory, and GCC 4.6 will also allow that. The compiler does not need to move the stack around at all, even for the systems that have discontiguous virtual addresses for the stack; they just change where new parts are allocated. The operating system might remap physical pages to virtual ones so that the stack may not be contiguous in physical memory, though, even if it is in virtual memory.