Finita la conversione dei listati in file separati. Passato anche alla nuova

[gapil.git] / listati / MutexLocking.c

diff --git a/listati/MutexLocking.c b/listati/MutexLocking.c
new file mode 100644 (file)
index 0000000..1b45315
--- /dev/null
+++ b/listati/MutexLocking.c
@@ -0,0 +1,55 @@
+/* Function CreateMutex: Create a mutex using file locking. */
+int CreateMutex(const char *path_name)
+{
+    return open(path_name, O_EXCL|O_CREAT);
+}
+/* Function UnlockMutex: unlock a file. */
+int FindMutex(const char *path_name)
+{
+    return open(path_name, O_RDWR);
+}
+/* Function LockMutex: lock mutex using file locking. */
+int LockMutex(int fd)
+{
+    struct flock lock;                                /* file lock structure */
+    /* set flock structure */
+    lock.l_type = F_WRLCK;                        /* set type: read or write */
+    lock.l_whence = SEEK_SET;        /* start from the beginning of the file */
+    lock.l_start = 0;                  /* set the start of the locked region */
+    lock.l_len = 0;                   /* set the length of the locked region */
+    /* do locking */
+    return fcntl(fd, F_SETLKW, &lock);
+}
+/* Function UnlockMutex: unlock a file. */
+int UnlockMutex(int fd)
+{
+    struct flock lock;                                /* file lock structure */
+    /* set flock structure */
+    lock.l_type = F_UNLCK;                               /* set type: unlock */
+    lock.l_whence = SEEK_SET;        /* start from the beginning of the file */
+    lock.l_start = 0;                  /* set the start of the locked region */
+    lock.l_len = 0;                   /* set the length of the locked region */
+    /* do locking */
+    return fcntl(fd, F_SETLK, &lock);
+}
+/* Function RemoveMutex: remove a mutex (unlinking the lock file). */
+int RemoveMutex(const char *path_name)
+{
+    return unlink(path_name);
+}
+/* Function ReadMutex: read a mutex status. */
+int ReadMutex(int fd)
+{
+    int res;
+    struct flock lock;                                /* file lock structure */
+    /* set flock structure */
+    lock.l_type = F_WRLCK;                               /* set type: unlock */
+    lock.l_whence = SEEK_SET;        /* start from the beginning of the file */
+    lock.l_start = 0;                  /* set the start of the locked region */
+    lock.l_len = 0;                   /* set the length of the locked region */
+    /* do locking */
+    if ( (res = fcntl(fd, F_GETLK, &lock)) ) {
+        return res;
+    }
+    return lock.l_type;
+}