lock.h File Reference

#include <lwp/lwp.h>

Include dependency graph for lock.h:

Go to the source code of this file.

Classes
struct	Lock

Macros
#define	EXCL_LOCKS   (WRITE_LOCK | SHARED_LOCK)

Typedefs
typedef struct Lock	Lock

Enumerations
enum	lock_how { READ_LOCK = 1 , WRITE_LOCK = 2 , SHARED_LOCK = 4 }

Functions
void	Lock_Obtain (struct Lock *lock, int how)
void	Lock_ReleaseR (struct Lock *lock)
void	Lock_ReleaseW (struct Lock *lock)
void	ObtainReadLock (struct Lock *lock)
void	ObtainWriteLock (struct Lock *lock)
void	ObtainSharedLock (struct Lock *lock)
void	ReleaseReadLock (struct Lock *lock)
void	ReleaseWriteLock (struct Lock *lock)
void	ReleaseSharedLock (struct Lock *lock)
int	CheckLock (struct Lock *lock)
int	WriteLocked (struct Lock *lock)
void	Lock_Init (struct Lock *lock)
void	ObtainDualLock (struct Lock *lock_1, enum lock_how how_1, struct Lock *lock_2, enum lock_how how_2)
void	ReleaseDualLock (struct Lock *lock_1, enum lock_how how_1, struct Lock *lock_2, enum lock_how how_2)

Macro Definition Documentation

EXCL_LOCKS

#define EXCL_LOCKS   (WRITE_LOCK | SHARED_LOCK)

Typedef Documentation

Lock

typedef struct Lock Lock

Enumeration Type Documentation

lock_how

enum lock_how

Locking type

Enumerator
READ_LOCK	lock for reading
WRITE_LOCK	lock for writing
SHARED_LOCK	as a shared lock

Function Documentation

CheckLock()

int CheckLock

(

struct Lock *

lock

)

Check the status of the lock

Parameters

lock	pointer to the lock

Returns

0 ff the lock is not acquired. If the lock is currently acquired for reading returns the amount of readers. And -1 if the lock is acquired obtained for writing or as a shared lock.

Lock_Init()

void Lock_Init

(

struct Lock *

lock

)

Initialize the Lock structure

Parameters

lock	pointer to the lock

Lock_Obtain()

void Lock_Obtain	(	struct Lock *	lock,
		int	how
	)

Obtain the lock

Parameters

lock	pointer to the lock
how	locking type

Lock_ReleaseR()

void Lock_ReleaseR

(

struct Lock *

lock

)

Release lock obtained for reading

Parameters

lock	pointer to the lock

Lock_ReleaseW()

void Lock_ReleaseW

(

struct Lock *

lock

)

Release lock obtained for writing

Parameters

lock	pointer to the lock

ObtainDualLock()

void ObtainDualLock	(	struct Lock *	lock_1,
		enum lock_how	how_1,
		struct Lock *	lock_2,
		enum lock_how	how_2
	)

Safely obtain two simultaneous locks

Parameters

lock_1	pointer to the first lock
how_1	first lock's type
lock_2	pointer to the second lock
how_2	second lock's type

ObtainReadLock()

void ObtainReadLock

(

struct Lock *

lock

)

Obtain the lock for reading

Parameters

lock	pointer to the lock

ObtainSharedLock()

void ObtainSharedLock

(

struct Lock *

lock

)

Obtain the lock as shared lock

Parameters

lock	pointer to the lock

ObtainWriteLock()

void ObtainWriteLock

(

struct Lock *

lock

)

Obtain the lock for writing

Parameters

lock	pointer to the lock

ReleaseDualLock()

void ReleaseDualLock	(	struct Lock *	lock_1,
		enum lock_how	how_1,
		struct Lock *	lock_2,
		enum lock_how	how_2
	)

Safely release two simultaneous locks

Parameters

lock_1	pointer to the first lock
how_1	first lock's type
lock_2	pointer to the second lock
how_2	second lock's type

ReleaseReadLock()

void ReleaseReadLock

(

struct Lock *

lock

)

Release the lock obtained for reading

Parameters

lock	pointer to the lock

ReleaseSharedLock()

void ReleaseSharedLock

(

struct Lock *

lock

)

Release the lock obtained as a shared lock

Parameters

lock	pointer to the lock

ReleaseWriteLock()

void ReleaseWriteLock

(

struct Lock *

lock

)

Release the lock obtained for writing

Parameters

lock	pointer to the lock

WriteLocked()

int WriteLocked

(

struct Lock *

lock

)

Check if the lock was acquired for reading

Parameters

lock	pointer to the lock

Returns

true (different than zero) if the lock is currently acquired for writing or as a shared lock. 0 otherwise.