semaphores.h File Reference

Wrappers around the sem* functions. More...

Go to the source code of this file.

Defines
#define	CF_SEM_LOCK(id, sem)   (cf_sem_pv(id,-1,sem))
#define	CF_SEM_DOWN(id, sem)   (cf_sem_pv(id,-1,sem))
#define	CF_SEM_UNLOCK(id, sem)   (cf_sem_pv(id,1,sem))
#define	CF_SEM_UP(id, sem)   (cf_sem_pv(id,1,sem))
#define	CF_SEM_WAITZERO(id, sem)   (cf_sem_pv(id,0,sem))
Functions
int	cf_sem_pv (int id, int operation, int semnum)
	This function performs semaphore operations.
int	cf_sem_getval (int id, int semnum, int num, unsigned short *val)

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Detailed Description

Wrappers around the sem* functions.

Author:

Christian Kruse, <cjk@wwwtech.de>

This module provides some wrapper functions for the semaphore functions provided by POSIX. These functions make the handling of semaphores much easier

Definition in file semaphores.h.

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Define Documentation

#define CF_SEM_DOWN (  id, sem   )     (cf_sem_pv(id,-1,sem))

This macro decreases the value of a semaphore by 1 Definition at line 40 of file semaphores.h.

#define CF_SEM_LOCK (  id, sem   )     (cf_sem_pv(id,-1,sem))

This macro decreases the value of the semaphore by 1 (equivalent to the P() action) Definition at line 35 of file semaphores.h.

#define CF_SEM_UNLOCK (  id, sem   )     (cf_sem_pv(id,1,sem))

This macro increases the value of the semaphore by 1 (equivalent to the V() action) Definition at line 45 of file semaphores.h.

#define CF_SEM_UP (  id, sem   )     (cf_sem_pv(id,1,sem))

This macro increases the value of the semaphore by 1 Definition at line 50 of file semaphores.h.

#define CF_SEM_WAITZERO (  id, sem   )     (cf_sem_pv(id,0,sem))

This macro blocks until the specified semaphore has reached a zero value Definition at line 55 of file semaphores.h.

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Function Documentation

int cf_sem_getval (  int  id, int  semnum, int  num, unsigned short *  val )

This function returns the value of the selected semaphore Parameters: id  The semaphore ide semnum  The semaphore index in the set num  The number of semaphores in the set val  Reference to a integer variable where to store the value Returns: 0 on success, -1 on failure Definition at line 55 of file semaphores.c.

int cf_sem_pv (  int  id, int  operation, int  semnum )

This function performs semaphore operations. Parameters: id  The semaphore id operation  The size to increase or decrease the value of the semaphore. semnum  The index of the semaphore in the set. Returns: 0 on success, -1 on failure Definition at line 46 of file semaphores.c.

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