Which of the following components of program state is shared across threads in a multithreaded process?
Register values, Heap Memory, Global Variables and Stack memory.
My suggestion; Only global variables, global variables are allocated on the heap? So Heap memory and Global Variables. Is this correct?
Heap memory always.
Global variables depends on platform, usually they are shared.
Stack is thread-specific, as well as registers.
It depends on the language and the thread implementation. For example, I don't think that even C lets you directly access the CPU registers, so it's rather moot whether, say, pthreads shares registers (which, for the record, I am fairly certain it does not). Also in C, global variables are not in fact allocated on the heap, though they may be in other languages.
The stack is more complicated. In C/pthreads, each thread has its own stack, but in other languages and threading models, the situation could be far more complicated simply because the underlying stack models may not be so simple.
stack : no
registers: no
heap: yes (if you have to choose y or n, the true answers is it depends)
globals: yes