diff --git a/server/console.c b/server/console.c
index a513538615c..cc574185a59 100644
--- a/server/console.c
+++ b/server/console.c
@@ -371,7 +371,7 @@ void inherit_console(struct thread *parent_thread, struct process *process, obj_
 
 static struct console_input* console_input_get( obj_handle_t handle, unsigned access )
 {
-    struct console_input*	console = 0;
+    struct console_input*	console = NULL;
 
     if (handle)
 	console = (struct console_input *)get_handle_obj( current->process, handle,
diff --git a/server/fd.c b/server/fd.c
index 72c3d9faa7c..6d6b00855ea 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -1042,7 +1042,7 @@ struct async *create_async(struct thread *thread, int* timeout, struct list *que
     {
         struct timeval when;
 
-        gettimeofday( &when, 0 );
+        gettimeofday( &when, NULL );
         add_timeout( &when, *timeout );
         async->timeout = add_timeout_user( &when, async_callback, async );
     }
diff --git a/server/file.c b/server/file.c
index 45f2bc0a8a6..8d237950d7a 100644
--- a/server/file.c
+++ b/server/file.c
@@ -297,7 +297,7 @@ static void file_queue_async( struct fd *fd, void *apc, void *user, void *iosb,
         return;
     }
 
-    if (!create_async( current, 0, queue, apc, user, iosb ))
+    if (!create_async( current, NULL, queue, apc, user, iosb ))
         return;
 
     /* Check if the new pending request can be served immediately */
diff --git a/server/mailslot.c b/server/mailslot.c
index 09000e64c83..6f24126a475 100644
--- a/server/mailslot.c
+++ b/server/mailslot.c
@@ -365,7 +365,7 @@ static struct mail_writer *create_mail_writer( struct mailslot *mailslot, unsign
            !((sharing & FILE_SHARE_WRITE) && (writer->sharing & FILE_SHARE_WRITE)))
         {
             set_error( STATUS_SHARING_VIOLATION );
-            return 0;
+            return NULL;
         }
     }
 
diff --git a/server/main.c b/server/main.c
index f1901cae6b8..3e258682114 100644
--- a/server/main.c
+++ b/server/main.c
@@ -111,7 +111,7 @@ static void parse_args( int argc, char *argv[] )
     }
 }
 
-static void sigterm_handler()
+static void sigterm_handler( int signum )
 {
     exit(1);  /* make sure atexit functions get called */
 }
diff --git a/server/named_pipe.c b/server/named_pipe.c
index 5dfc35990fd..c8358dca01a 100644
--- a/server/named_pipe.c
+++ b/server/named_pipe.c
@@ -364,7 +364,7 @@ static void check_flushed( void *arg )
     {
         struct timeval tv;
 
-        gettimeofday( &tv, 0 );
+        gettimeofday( &tv, NULL );
         add_timeout( &tv, 100 );
         server->flush_poll = add_timeout_user( &tv, check_flushed, server );
     }
@@ -402,7 +402,7 @@ static int pipe_server_flush( struct fd *fd, struct event **event )
         server->event = create_event( NULL, 0, 0, 0 );
         if( !server->event )
             return 0;
-        gettimeofday( &tv, 0 );
+        gettimeofday( &tv, NULL );
         add_timeout( &tv, 100 );
         server->flush_poll = add_timeout_user( &tv, check_flushed, server );
         *event = server->event;
diff --git a/server/process.c b/server/process.c
index 24a34c87dad..eb869ec81df 100644
--- a/server/process.c
+++ b/server/process.c
@@ -1181,7 +1181,7 @@ DECL_HANDLER(get_dll_info)
         if (dll)
         {
             reply->size = dll->size;
-            reply->entry_point = 0; /* FIXME */
+            reply->entry_point = NULL; /* FIXME */
             if (dll->filename)
             {
                 size_t len = min( dll->namelen, get_reply_max_size() );
diff --git a/server/queue.c b/server/queue.c
index e0fef71da5a..38e5d6754d9 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -531,7 +531,7 @@ static struct message_result *alloc_message_result( struct msg_queue *send_queue
         if (timeout != -1)
         {
             struct timeval when;
-            gettimeofday( &when, 0 );
+            gettimeofday( &when, NULL );
             add_timeout( &when, timeout );
             result->timeout = add_timeout_user( &when, result_timeout, result );
         }
@@ -960,7 +960,7 @@ static void restart_timer( struct msg_queue *queue, struct timer *timer )
     struct timeval now;
 
     list_remove( &timer->entry );
-    gettimeofday( &now, 0 );
+    gettimeofday( &now, NULL );
     while (!time_before( &now, &timer->when )) add_timeout( &timer->when, timer->rate );
     link_timer( queue, timer );
     set_next_timer( queue );
@@ -993,7 +993,7 @@ static struct timer *set_timer( struct msg_queue *queue, unsigned int rate )
     if (timer)
     {
         timer->rate  = max( rate, 1 );
-        gettimeofday( &timer->when, 0 );
+        gettimeofday( &timer->when, NULL );
         add_timeout( &timer->when, rate );
         link_timer( queue, timer );
         /* check if we replaced the next timer */
diff --git a/server/region.c b/server/region.c
index ea9cf695c28..9a3891aef25 100644
--- a/server/region.c
+++ b/server/region.c
@@ -111,7 +111,7 @@ static inline rectangle_t *add_rect( struct region *reg )
         if (!new_rect)
         {
             set_error( STATUS_NO_MEMORY );
-            return 0;
+            return NULL;
         }
         reg->rects = new_rect;
         reg->size *= 2;
diff --git a/server/registry.c b/server/registry.c
index 1c7a0d8b2a3..5d2d0b9ba34 100644
--- a/server/registry.c
+++ b/server/registry.c
@@ -452,7 +452,7 @@ static void make_clean( struct key *key )
 }
 
 /* go through all the notifications and send them if necessary */
-void check_notify( struct key *key, unsigned int change, int not_subtree )
+static void check_notify( struct key *key, unsigned int change, int not_subtree )
 {
     struct list *ptr, *next;
 
@@ -1644,10 +1644,10 @@ static void set_periodic_save_timer(void)
 {
     struct timeval next;
 
-    gettimeofday( &next, 0 );
+    gettimeofday( &next, NULL );
     add_timeout( &next, save_period );
     if (save_timeout_user) remove_timeout_user( save_timeout_user );
-    save_timeout_user = add_timeout_user( &next, periodic_save, 0 );
+    save_timeout_user = add_timeout_user( &next, periodic_save, NULL );
 }
 
 /* save the modified registry branches to disk */
diff --git a/server/request.c b/server/request.c
index 8d33660bf66..aa5c09de58d 100644
--- a/server/request.c
+++ b/server/request.c
@@ -813,7 +813,7 @@ void close_master_socket(void)
 
     if (master_socket_timeout)
     {
-        gettimeofday( &when, 0 );
+        gettimeofday( &when, NULL );
         add_timeout( &when, master_socket_timeout * 1000 );
         master_socket->timeout = add_timeout_user( &when, close_socket_timeout, NULL );
     }
diff --git a/server/signal.c b/server/signal.c
index 470a476de9d..f3b0f5f7dd8 100644
--- a/server/signal.c
+++ b/server/signal.c
@@ -181,25 +181,25 @@ static void sigint_callback(void)
 }
 
 /* SIGHUP handler */
-static void do_sighup()
+static void do_sighup( int signum )
 {
     do_signal( handler_sighup );
 }
 
 /* SIGTERM handler */
-static void do_sigterm()
+static void do_sigterm( int signum )
 {
     do_signal( handler_sigterm );
 }
 
 /* SIGINT handler */
-static void do_sigint()
+static void do_sigint( int signum )
 {
     do_signal( handler_sigint );
 }
 
 /* SIGCHLD handler */
-static void do_sigchld()
+static void do_sigchld( int signum )
 {
     do_signal( handler_sigchld );
 }
diff --git a/server/snapshot.c b/server/snapshot.c
index 61265badfe6..7f1670c6100 100644
--- a/server/snapshot.c
+++ b/server/snapshot.c
@@ -125,8 +125,8 @@ static int snapshot_next_process( struct snapshot *snapshot, struct next_process
     reply->count    = ptr->count;
     reply->pid      = get_process_id( ptr->process );
     reply->ppid     = ptr->process->parent ? get_process_id( ptr->process->parent ) : 0;
-    reply->heap     = 0;  /* FIXME */
-    reply->module   = 0;  /* FIXME */
+    reply->heap     = NULL;  /* FIXME */
+    reply->module   = NULL;  /* FIXME */
     reply->threads  = ptr->threads;
     reply->priority = ptr->priority;
     reply->handles  = ptr->handles;
diff --git a/server/sock.c b/server/sock.c
index 7fcb406f702..3fa3049b976 100644
--- a/server/sock.c
+++ b/server/sock.c
@@ -529,7 +529,7 @@ static void sock_queue_async( struct fd *fd, void *apc, void *user, void *iosb,
     }
     else
     {
-        if (!create_async( current, 0, queue, apc, user, iosb ))
+        if (!create_async( current, NULL, queue, apc, user, iosb ))
             return;
     }
 
@@ -674,7 +674,7 @@ static struct sock *accept_socket( obj_handle_t handle )
         acceptsock->wparam  = 0;
         if (sock->event) acceptsock->event = (struct event *)grab_object( sock->event );
         acceptsock->flags = sock->flags;
-        acceptsock->deferred = 0;
+        acceptsock->deferred = NULL;
         if (!(acceptsock->fd = create_anonymous_fd( &sock_fd_ops, acceptfd, &acceptsock->obj )))
         {
             release_object( acceptsock );
diff --git a/server/timer.c b/server/timer.c
index 720c6f328cc..2329c6c262e 100644
--- a/server/timer.c
+++ b/server/timer.c
@@ -147,7 +147,7 @@ static int set_timer( struct timer *timer, const abs_time_t *expire, int period,
     if (!expire->sec && !expire->usec)
     {
         /* special case: use now + period as first expiration */
-        gettimeofday( &timer->when, 0 );
+        gettimeofday( &timer->when, NULL );
         add_timeout( &timer->when, period );
     }
     else