swapcontext
int swapcontext(ucontext_t * __restrict, const ucontext_t * __restrict);
swapcontext(&pcc->pcc_uc, &jumpcc->pcc_uc);
swapcontext(&pcc->pcc_uc_ret, &pcc->pcc_uc);
swapcontext(&loanpcc->pcc_uc_ret, &loanpcc->pcc_uc);
swapcontext(&pcc->pcc_uc, &pcc->pcc_uc_ret);
ret = swapcontext(&prev->ctx, &next->ctx);
return swapcontext(oucp, ucp);
RL(swapcontext(&return_context, &uc));
RL(swapcontext(&return_context, &uc));
RL(swapcontext(&return_context, &uc1));
RL(swapcontext(&return_context, &uc1));
ATF_REQUIRE(swapcontext(&nctx, &octx));
ATF_REQUIRE(swapcontext(&octx, &nctx) == 0);
ATF_REQUIRE_MSG(swapcontext(&octx, &nctx) != -1, "swapcontext failed: %s",