Ajout Exo1

ANALE-1/EXO1/SUJET/dijkstra.c

@@ -0,0 +1,57 @@
+#include <sys/sem.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "dijkstra.h"
+
+int sem_create(key_t cle, int initval) {
+	int semid;
+	union semun { int val; struct semid_ds *buf; ushort *array; } arg_ctl;
+
+	semid = semget(cle, 1 , IPC_CREAT|IPC_EXCL|0666);
+	if (semid == -1) 
+	{
+		semid = semget(cle,1, 0666);
+		if (semid == -1) 
+		{
+			perror("Erreur semget()"); 
+			exit(1);
+		}
+	}
+	else 
+	{ 
+		arg_ctl.val = initval;
+		if (semctl(semid, 0, SETVAL, arg_ctl) == -1) 
+		{
+			perror("Erreur initialisation sémaphore"); 
+			exit(1);
+		}
+	}
+	return(semid) ;
+}
+
+void P(int semid) 
+{
+	struct sembuf sempar;
+	sempar.sem_num = 0;
+	sempar.sem_op = -1;
+	sempar.sem_flg = 0;
+	if (semop(semid, &sempar, 1) == -1) 
+		perror("Erreur operation P");
+}
+
+void V(int semid) 
+{
+	struct sembuf sempar;
+	sempar.sem_num = 0;
+	sempar.sem_op = 1;
+	sempar.sem_flg = 0;
+	if (semop(semid, &sempar, 1) == -1) 
+		perror("Erreur opération V");
+}
+
+void sem_delete(int semid) 
+{
+	if (semctl(semid,0,IPC_RMID,0) == -1) 
+		perror("Erreur dans destruction sémaphore");
+}