1 /* Swap to new context. 2 Copyright (C) 2008-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library. If not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #include <ucontext.h> 20 21 extern int __getcontext (ucontext_t *ucp); 22 extern int __setcontext (const ucontext_t *ucp); 23 24 int __swapcontext(ucontext_t * oucp,const ucontext_t * ucp)25__swapcontext (ucontext_t *oucp, const ucontext_t *ucp) 26 { 27 /* Save the current machine context to oucp. */ 28 __getcontext (oucp); 29 30 /* mark sc_sar flag to skip the setcontext call on reactivation. */ 31 if (oucp->uc_mcontext.sc_sar == 0) { 32 oucp->uc_mcontext.sc_sar++; 33 34 /* Restore the machine context in ucp. */ 35 __setcontext (ucp); 36 } 37 38 return 0; 39 } 40 41 weak_alias (__swapcontext, swapcontext) 42