semaphore.h File Reference

#include <stdint.h>

Include dependency graph for semaphore.h:

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Data Structures
union	sem_t

Macros
#define	__SIZEOF_SEM_T   12 /* sizeof(struct semaphore) */

Functions
int	sem_init (sem_t *sem, int pshared, unsigned int value)
	Initialize the semaphore. More...
int	sem_destroy (sem_t *sem)
	Destroy the semaphore. More...
int	sem_post (sem_t *sem)
	Increase the value of the semaphore. More...
int	sem_trywait (sem_t *sem)
	The same as sem_wait(), except that if the decrement cannot be immediately performed, then the function returns an error instead of blocking. More...
int	sem_wait (sem_t *sem)
	Decrement the value of the semaphore. If the semaphore currently has the value zero, then the function blocks until it becomes possible to perform the decrement. More...
int	sem_getvalue (sem_t *sem, int *sval)
	Get the value of the semaphore. More...

Function Documentation

sem_destroy()

int sem_destroy

(

sem_t *

sem

)

Destroy the semaphore.

Parameters

sem	Pointer to the semaphore.

Return values

int	0 on success and nonzero error number on error.

sem_getvalue()

int sem_getvalue	(	sem_t *	sem,
		int *	sval
	)

Get the value of the semaphore.

Parameters

sem	The semaphore object to provide.
sval	For returning current value of the semaphore.

Return values

int	0 on success and nonzero error number on error.

sem_init()

int sem_init	(	sem_t *	sem,
		int	pshared,
		unsigned int	value
	)

Initialize the semaphore.

Parameters

sem	Pointer to the semaphore.
pshared	Not used.
value	The initial value of the semaphore.

Return values

int	0 on success and nonzero error number on error.

sem_post()

int sem_post

(

sem_t *

sem

)

Increase the value of the semaphore.

Parameters

sem	Pointer to the semaphore.

Return values

int	0 on success and nonzero error number on error.

sem_trywait()

int sem_trywait

(

sem_t *

sem

)

The same as sem_wait(), except that if the decrement cannot be immediately performed, then the function returns an error instead of blocking.

Parameters

sem	Pointer to the semaphore.

Return values

int	0 on success and nonzero error number on error.

sem_wait()

int sem_wait

(

sem_t *

sem

)

Decrement the value of the semaphore. If the semaphore currently has the value zero, then the function blocks until it becomes possible to perform the decrement.

Parameters

sem	Pointer to the semaphore.

Return values

int	0 on success and nonzero error number on error.