1 /* Machine-specific definition for spin locks. Stub version. 2 Copyright (C) 1994-2021 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 #ifndef _MACHINE_LOCK_H 20 #define _MACHINE_LOCK_H 21 22 /* The type of a spin lock variable. */ 23 24 typedef volatile int __spin_lock_t; 25 26 /* Value to initialize `__spin_lock_t' variables to. */ 27 28 #define __SPIN_LOCK_INITIALIZER 0 29 30 31 #ifndef _EXTERN_INLINE 32 #define _EXTERN_INLINE __extern_inline 33 #endif 34 35 /* Unlock LOCK. */ 36 37 extern void __spin_unlock (__spin_lock_t *__lock); 38 39 #if defined __USE_EXTERN_INLINES && defined _LIBC 40 _EXTERN_INLINE void __spin_unlock(__spin_lock_t * __lock)41__spin_unlock (__spin_lock_t *__lock) 42 { 43 *__lock = 0; 44 } 45 #endif 46 47 /* Try to lock LOCK; return nonzero if we locked it, zero if another has. */ 48 49 extern int __spin_try_lock (__spin_lock_t *__lock); 50 51 #if defined __USE_EXTERN_INLINES && defined _LIBC 52 _EXTERN_INLINE int __spin_try_lock(__spin_lock_t * __lock)53__spin_try_lock (__spin_lock_t *__lock) 54 { 55 if (*__lock) 56 return 0; 57 *__lock = 1; 58 return 1; 59 } 60 #endif 61 62 /* Return nonzero if LOCK is locked. */ 63 64 extern int __spin_lock_locked (__spin_lock_t *__lock); 65 66 #if defined __USE_EXTERN_INLINES && defined _LIBC 67 _EXTERN_INLINE int __spin_lock_locked(__spin_lock_t * __lock)68__spin_lock_locked (__spin_lock_t *__lock) 69 { 70 return *__lock != 0; 71 } 72 #endif 73 74 75 #endif /* machine-lock.h */ 76