diff --git a/common/shm.c b/common/shm.c
index ce05bb41..e74a2134 100644
--- a/common/shm.c
+++ b/common/shm.c
@@ -145,11 +145,11 @@ static int semid = -1;
 
 #ifdef WIN32
 
-static void
-semaphore_init () {}
+static int
+semaphore_init () {return 0;}
 
-static  void
-semaphore_add (int value) {}
+static  int
+semaphore_add (int value) {return 0;}
 
 #else
 /* all semaphore errors are fatal -- issue message, but do not return */
@@ -194,7 +194,7 @@ semaphore_init ()
             return -1;
 		}
 	}
-    
+
     return 0;
 }
 
@@ -206,12 +206,12 @@ semaphore_add (int value)
 	sbuf.sem_num = 0;
 	sbuf.sem_op = value;
 	sbuf.sem_flg = SEM_UNDO;
-    
+
 	if (semop(semid, &sbuf, 1) == -1) {
 		semaphore_error ("semop");
         return -1;
 	}
-    
+
     return 0;
 }
 
@@ -228,7 +228,7 @@ jack_shm_lock_registry (void)
 	return semaphore_add (-1);
 }
 
-static void 
+static void
 jack_shm_unlock_registry (void)
 {
 	semaphore_add (1);
@@ -370,7 +370,7 @@ jack_initialize_shm (const char *server_name)
         jack_error ("jack_shm_lock_registry fails...");
         return -1;
     }
-                    
+
 	if ((rc = jack_access_registry (&registry_info)) == 0) {
 		if ((rc = jack_shm_validate_registry ()) != 0) {
 			jack_error ("Incompatible shm registry, "
@@ -441,7 +441,7 @@ jack_release_shm_info (jack_shm_registry_index_t index)
 		jack_release_shm_entry (index);
 		jack_shm_unlock_registry ();
 	}
-    
+
     return 0;
 }
 
@@ -518,7 +518,7 @@ jack_register_server (const char *server_name, int new_registry)
 }
 
 /* release server_name registration */
-void
+int
 jack_unregister_server (const char *server_name /* unused */)
 {
 	int i;
@@ -534,7 +534,8 @@ jack_unregister_server (const char *server_name /* unused */)
 		}
 	}
 
-	jack_shm_unlock_registry ();
+	jack_shm_unlock_registry ();
+	return 0;
 }
 
 /* called for server startup and termination */
diff --git a/common/shm.h b/common/shm.h
index bff6a857..ed5a953f 100644
--- a/common/shm.h
+++ b/common/shm.h
@@ -115,33 +115,33 @@ extern "C"
      * indicating where the shared memory has been
      * attached to the address space.
      */
-     
+
     typedef struct _jack_shm_info {
         jack_shm_registry_index_t index;       /* offset into the registry */
         uint32_t size;
         union {
             void *attached_at;  /* address where attached */
-            char ptr_size[8];   
-        } ptr;  /* a "pointer" that has the same 8 bytes size when compling in 32 or 64 bits */ 
+            char ptr_size[8];
+        } ptr;  /* a "pointer" that has the same 8 bytes size when compling in 32 or 64 bits */
     }
     POST_PACKED_STRUCTURE jack_shm_info_t;
 
     /* utility functions used only within JACK */
-      
+
     void jack_shm_copy_from_registry (jack_shm_info_t*,
                 jack_shm_registry_index_t);
     void jack_shm_copy_to_registry (jack_shm_info_t*,
                                                jack_shm_registry_index_t*);
     int jack_release_shm_info (jack_shm_registry_index_t);
-    char* jack_shm_addr (jack_shm_info_t* si);  
+    char* jack_shm_addr (jack_shm_info_t* si);
 
-    // here begin the API 
+    // here begin the API
     int jack_register_server (const char *server_name, int new_registry);
-    void jack_unregister_server (const char *server_name);
+    int jack_unregister_server (const char *server_name);
 
     int jack_initialize_shm (const char *server_name);
-    int jack_initialize_shm_server (void); 
-    int jack_initialize_shm_client (void);  
+    int jack_initialize_shm_server (void);
+    int jack_initialize_shm_client (void);
     int jack_cleanup_shm (void);
 
     int jack_shmalloc (const char *shm_name, jack_shmsize_t size,
@@ -149,7 +149,7 @@ extern "C"
     void jack_release_shm (jack_shm_info_t*);
     void jack_destroy_shm (jack_shm_info_t*);
     int jack_attach_shm (jack_shm_info_t*);
-    int jack_attach_shm_read (jack_shm_info_t*); 
+    int jack_attach_shm_read (jack_shm_info_t*);
     int jack_resize_shm (jack_shm_info_t*, jack_shmsize_t size);
 
 #ifdef __cplusplus