ucontext_t uc_link sigset_t uc_sigmask stack_t uc_stack mcontext_t uc_mcontextThe
uc_linkfield is a pointer to the context to be resumed when the context returns. This context is the main context when
uc_linkis set to zero; the process exits when this context returns.
uc_sigmask defines a set of signals to be blocked when the
context is active (see
uc_stack defines the stack to be used by the context (see
uc_mcontext contains the set of saved machine
registers. Note that this field should not be accessed or modified
by applications intended to be portable.