X-Git-Url: https://gapil.gnulinux.it/gitweb/?p=gapil.git;a=blobdiff_plain;f=listati%2FMutexLocking.c;fp=listati%2FMutexLocking.c;h=1b453154f2a9f51026d8dbb0ab524bebac52a9a4;hp=0000000000000000000000000000000000000000;hb=06661f47754a536098afe2b30cb04469918f2fa3;hpb=bdf6e88eeb9b3aef06d57930ec8b89083639e56d

diff --git a/listati/MutexLocking.c b/listati/MutexLocking.c
new file mode 100644
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;
+}