58 lines
1.0 KiB
C
58 lines
1.0 KiB
C
#include <sys/sem.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include "dijkstra.h"
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int sem_create(key_t cle, int initval) {
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int semid;
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union semun { int val; struct semid_ds *buf; ushort *array; } arg_ctl;
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semid = semget(cle, 1 , IPC_CREAT|IPC_EXCL|0666);
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if (semid == -1)
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{
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semid = semget(cle,1, 0666);
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if (semid == -1)
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{
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perror("Erreur semget()");
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exit(1);
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}
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}
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else
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{
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arg_ctl.val = initval;
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if (semctl(semid, 0, SETVAL, arg_ctl) == -1)
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{
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perror("Erreur initialisation sémaphore");
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exit(1);
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}
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}
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return(semid) ;
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}
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void P(int semid)
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{
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struct sembuf sempar;
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sempar.sem_num = 0;
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sempar.sem_op = -1;
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sempar.sem_flg = 0;
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if (semop(semid, &sempar, 1) == -1)
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perror("Erreur operation P");
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}
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void V(int semid)
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{
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struct sembuf sempar;
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sempar.sem_num = 0;
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sempar.sem_op = 1;
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sempar.sem_flg = 0;
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if (semop(semid, &sempar, 1) == -1)
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perror("Erreur opération V");
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}
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void sem_delete(int semid)
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{
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if (semctl(semid,0,IPC_RMID,0) == -1)
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perror("Erreur dans destruction sémaphore");
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}
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