This entry in the thread control block (i.e., the uthread_t structure)

What is this?

It is a data structure to hold:

• The thread's signal mask
• Its execution stack
• Machine register values

Linux provides functions for initializing and swapping this context information:

• int getcontext(ucontext_t *ucp)
• int setcontext(const ucontext_t *ucp)
• int swapcontext(ucontext_t *olducp, ucontext_t *newucp)
• void makecontext(ucontext_t *ucp, void *f(), int argc, ...)