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/*
* BRLTTY - A background process providing access to the console screen (when in
* text mode) for a blind person using a refreshable braille display.
*
* Copyright (C) 1995-2014 by The BRLTTY Developers.
*
* BRLTTY comes with ABSOLUTELY NO WARRANTY.
*
* This is free software, placed under the terms of the
* GNU General Public License, as published by the Free Software
* Foundation; either version 2 of the License, or (at your option) any
* later version. Please see the file LICENSE-GPL for details.
*
* Web Page: http://mielke.cc/brltty/
*
* This software is maintained by Dave Mielke <dave@mielke.cc>.
*/
#ifndef BRLTTY_INCLUDED_LOCK
#define BRLTTY_INCLUDED_LOCK
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
typedef struct LockDescriptorStruct LockDescriptor;
typedef enum {
LOCK_Exclusive = 0X1,
LOCK_NoWait = 0X2
} LockOptions;
extern LockDescriptor *newLockDescriptor (void);
extern LockDescriptor *getLockDescriptor (LockDescriptor **lock);
extern void freeLockDescriptor (LockDescriptor *lock);
extern int obtainLock (LockDescriptor *lock, LockOptions options);
extern void releaseLock (LockDescriptor *lock);
static inline void obtainExclusiveLock (LockDescriptor *lock) {
obtainLock(lock, LOCK_Exclusive);
}
static inline void obtainSharedLock (LockDescriptor *lock) {
obtainLock(lock, 0);
}
static inline int tryExclusiveLock (LockDescriptor *lock) {
return obtainLock(lock, LOCK_Exclusive | LOCK_NoWait);
}
static inline int trySharedLock (LockDescriptor *lock) {
return obtainLock(lock, LOCK_NoWait);
}
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* BRLTTY_INCLUDED_LOCK */
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