The uc_link field points to the context to resume when this context’s entry point function returns. If uc_link is equal to NULL, then the process exits when this context returns.
The uc_mcontext field is machine-dependent and should be treated as opaque by portable applications.
The following functions are defined to manipulate .Vt ucontext_t structures:
int getcontext "ucontext_t *";
int setcontext "const ucontext_t *";
void makecontext "ucontext_t *" "void lp]*rp]lp]voidrp]" int ...;
int swapcontext "ucontext_t *" "const ucontext_t *";
