semaphores.h File Reference

Software API for an easy use of the *nix IPC system. More...

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <errno.h>
#include <unistd.h>
#include <sys/sem.h>
#include <sys/ipc.h>
#include <fcntl.h>

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Classes
struct	semaphore
	Structure where all semaphore related data is stored. More...
Defines
#define	MAX_SEMFILENAME_SIZE   128
Typedefs
typedef struct semaphore	semaphore_t
	Structure where all semaphore related data is stored.
Functions
int	createKey (key_t *, char[])
	Create keys from a file to be used by a semaphore.
int	freeSem (int semID)
	Frees a taken semaphore.
int	getSemID (key_t, int *semID)
	Gets a semaphore identification.
int	rmSem (int semID)
	Removes a semaphore set.
int	waitSem (int semID)
	waits for a semaphore until its resources are free

---

Detailed Description

Software API for an easy use of the *nix IPC system.

Author:

Raul Perula-Martinez <raul.perula@uc3m.es>

Date:

2015-03

Author:

Victor Gonzalez <vgonzale@ing.uc3m.es>

Date:

2010-01

Copyright:

Copyright (C) 2015 University Carlos III of Madrid. All rights reserved. LEUC3M v1.0, see LICENSE.txt

This program is free software: you can redistribute it and/or modify it under the terms of the Licencia Educativa UC3M as published by the University Carlos III of Madrid, either version 1.0, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY. See the Licencia Educativa UC3M version 1.0 or any later version for more details.

A copy of the Licencia Educativa UC3M is in the LICENSE file.

Definition in file semaphores.h.

---

Define Documentation

#define MAX_SEMFILENAME_SIZE   128

Definition at line 45 of file semaphores.h.

---

Typedef Documentation

typedef struct semaphore semaphore_t

Structure where all semaphore related data is stored.

---

Function Documentation

int createKey	(	key_t *	,
		char	[]
	)

Create keys from a file to be used by a semaphore.

Parameters:

semKey	pointer to the created key
semFile	full path of the file. If the file does not exists it is created.

Returns:

-1 if an error while creating the file happened.

-2 if a file-to-key error happened

semKey in case of success

int freeSem

(

int

semID

)

Frees a taken semaphore.

Parameters:

semID

is the identifier of the semaphore

Returns:

0 if everything goes correctly

-1 if there is an error in semop operation

Definition at line 102 of file semaphores.c.

int getSemID	(	key_t	,
		int *	semID
	)

Gets a semaphore identification.

Parameters:

semKey
semID	is where the semaphore identificator is stored

Returns:

-1 if there is an error in semget operation

-2 if there is an error in semctl operation

semID in case of success

Definition at line 50 of file semaphores.c.

int rmSem

(

int

semID

)

Removes a semaphore set.

Parameters:

semID

an integer with semaphore identification.

Returns:

0 if everything goes correctly

-1 if there is an error in semop operation

Definition at line 68 of file semaphores.c.

int waitSem

(

int

semID

)

waits for a semaphore until its resources are free

Parameters:

semID

an integer which identifies the semaphore

Returns:

0 if everything goes correctly

-1 if there is an error in semop operation

Definition at line 84 of file semaphores.c.