if (__getcontext (oucp) == 0) __setcontext (ucp);
__getcontext (oucp);  oucp->uc_mcontext.gregs[14] = &&fake_return;  __setcontext (ucp);  fake_return:
__swapcontext (ucontext_t *oucp, const ucontext_t *ucp){  if (__getcontext (oucp) == 0)    __setcontext (ucp);  return 0;}