X-Git-Url: https://gapil.gnulinux.it/gitweb/?p=gapil.git;a=blobdiff_plain;f=sources%2Fwrappers.h;h=15ddd826c2f3500668632b8d1cea932e6a95fef1;hp=ee8fa89da88d4d85489ae1bb209807408907eeab;hb=3498a6fc0fd13e07cacdea210cb99126d5052fbc;hpb=4ddd2ee63965e5eb0f723da634d157447f3e4ceb

diff --git a/sources/wrappers.h b/sources/wrappers.h
index ee8fa89..15ddd82 100644
--- a/sources/wrappers.h
+++ b/sources/wrappers.h
@@ -5,7 +5,7 @@
  *
  * Author: S. Piccardi
  *
- * $Id: wrappers.h,v 1.3 2002/08/18 23:24:44 piccardi Exp $
+ * $Id: wrappers.h,v 1.4 2002/11/20 23:34:02 piccardi Exp $
  *
  ***************************************************************/
 #include <sys/sem.h>     /* IPC semaphore declarations */
@@ -32,45 +32,8 @@ union semun {
 };
 #endif
 /*
- * Define the sem_lock and sem_ulock sembuf structures to 
- * lock and unlock the semaphore (used to implement a mutex)
- */
-struct sembuf sem_lock={      /* to lock semaphore */
-    0,    /* semaphore number (only one so 0) */
-    -1,   /* semaphore operation (-1 to use resource) */
-    0};   /* semaphore flag (in this case 0) */
-struct sembuf sem_ulock={     /* to unlock semaphore */
-    0,    /* semaphore number (only one so 0) */
-    1,    /* semaphore operation (-1 to release resource) */
-    0};   /* semaphore flag (in this case 0) */
-/*
- * Function MutexLock:
- * to lock a mutex/semaphore
- *
- * Input: a semaphore id #
- */
-inline void MutexLock(int sem_id) 
-{
-    if (semop(sem_id,&sem_lock,1)) {
-	perror("Cannot lock the semaphore");
-	exit(1);
-    }
-}
-/*
- * Function MutexUnlock
- * to unlock a mutex/semaphore
+ * Function MutexCreate: create a mutex/semaphore
  *
- * Input: a semaphore id #
- */
-inline void MutexUnlock(int sem_id) 
-{
-    if (semop(sem_id,&sem_ulock,1)) {
-	perror("Cannot unlock the semaphore");
-	exit(1);
-    }
-}
-/*
- * Function MutexCreate:
  * First call create a semaphore, using the given key. 
  * We want only one semaphore so we set second argument to 1; third 
  * parameter is the flag argument, and is set to create a semaphore 
@@ -78,55 +41,72 @@ inline void MutexUnlock(int sem_id)
  * Second call initialize the semaphore to 1 (unlocked)
  *
  * Input: an IPC key value (to create an unique semaphore)
- * Return: the semaphore id#
+ * Return: the semaphore id# or -1 on error
  */
-const union semun semunion={1};    /* semaphore union structure */
 inline int MutexCreate(key_t ipc_key) 
 {
-    int sem_id;
-    if( (sem_id=semget(ipc_key,1,IPC_CREAT|0666))<0 ){ /* get sem ID */
-	perror("cannot create semaphore");     /* a sem_id <0 is an error */
-	printf("semid=%d",sem_id);
-	exit(1);
+    const union semun semunion={1};             /* semaphore union structure */
+    int sem_id, ret;
+    sem_id = semget(ipc_key, 1, IPC_CREAT|0666);         /* get semaphore ID */
+    if (sem_id == -1) {                              /* if error return code */
+	return sem_id;
     }
-    if ( (semctl(sem_id,0,SETVAL,semunion)) < 0 ) {
-        perror("cannot init semaphore");       /* <0 is an error */
-	printf("on semid=%d",sem_id);
-	exit(1);
+    ret = semctl(sem_id, 0, SETVAL, semunion);             /* init semaphore */
+    if (ret == -1) {
+	return ret;
     }
     return sem_id;
 }
 /*
- * Find Mutex
- * get the semaphore/mutex Id given the IPC key value
+ * Function MutexFind: get the semaphore/mutex Id given the IPC key value
  *
  * Input: an IPC key value
  */
 inline int MutexFind(key_t ipc_key) 
 {
-    int sem_id;
-    if( (sem_id=semget(ipc_key,1,0))<0 ){       /* find sem .ID */
-	perror("cannot find semaphore");
-        exit(1);
-    }
-    return sem_id;
+    return semget(ipc_key,1,0);
 }
 /*
- * Function MutexRead:
- * Read the current value of the mutex/semaphore
+ * Function MutexRead: read the current value of the mutex/semaphore
  *
  * Input:  a semaphore id #
  * Return: the semaphore value
  */
 inline int MutexRead(int sem_id) 
 {
-    int value;
-    if ( (value=semctl(sem_id,0,GETVAL,semunion)) < 0 ) {
-	      perror("cannot read semaphore");       /* a <0 is an error */
-	      printf("on semid=%d\n",sem_id);
-	      exit(1);
-    } 
-    return value;
+    return semctl(sem_id, 0, GETVAL);
+}
+/*
+ * Define sembuf structures to lock and unlock the semaphore 
+ * (used to implement a mutex)
+ */
+struct sembuf sem_lock={                                /* to lock semaphore */
+    0,                                   /* semaphore number (only one so 0) */
+    -1,                                    /* operation (-1 to use resource) */
+    SEM_UNDO};                                /* flag (set for undo at exit) */
+struct sembuf sem_ulock={                             /* to unlock semaphore */
+    0,                                   /* semaphore number (only one so 0) */
+    1,                                  /* operation (1 to release resource) */
+    SEM_UNO};                                       /* flag (in this case 0) */
+/*
+ * Function MutexLock: to lock a mutex/semaphore
+ *
+ * Input:  a semaphore id #
+ * Output: semop return code  (0 OK, -1 KO)
+ */
+inline int MutexLock(int sem_id) 
+{
+    return semop(sem_id, &sem_lock, 1);
+}
+/*
+ * Function MutexUnlock: to unlock a mutex/semaphore
+ *
+ * Input:  a semaphore id #
+ * Return: semop return code (0 OK, -1 KO)
+ */
+inline int MutexUnlock(int sem_id) 
+{
+    return semop(sem_id, &sem_ulock, 1);
 }
 /*
  * Function ShmCreate: