refactor: replace C11 keywords with C23 equivalents, NULL→nullptr, remove stdbool.h

parser/parser.c

@@ -721,7 +721,7 @@ config_autostart_run(const Config *cfg)
 			continue;
 		}
 		if (cpid == 0) {
-			execl("/bin/sh", "sh", "-c", cmd, NULL);
+			execl("/bin/sh", "sh", "-c", cmd, nullptr);
 			fprintf(stderr, "peachwm autostart: exec '%s': %s\n",
 			        cmd, strerror(errno));
 			_exit(1);
@@ -750,7 +750,7 @@ config_autostart_run(const Config *cfg)
 				     now.tv_nsec >= deadline.tv_nsec))
 					break; /* looks like a daemon, move on */
 				struct timespec sl = { .tv_sec = 0, .tv_nsec = 50 * 1000 * 1000 };
-				nanosleep(&sl, NULL);
+				nanosleep(&sl, nullptr);
 			}
 		}
 	}
@@ -766,7 +766,7 @@ watch_dispatch(int fd, uint32_t mask, void *data)
 	WatchState *ws = data;
 
 	/* Drain the inotify events */
-	_Alignas(struct inotify_event) char buf[4096];
+	alignas(struct inotify_event) char buf[4096];
 	ssize_t len = read(fd, buf, sizeof(buf));
 	if (len < 0) {
 		if (errno != EAGAIN)
@@ -807,13 +807,13 @@ config_watch_start(struct wl_event_loop *loop, const char *path,
                    config_reload_cb cb, void *userdata)
 {
 	WatchState *ws = calloc(1, sizeof(*ws));
-	if (!ws) return NULL;
+	if (!ws) return nullptr;
 
 	ws->inotify_fd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
 	if (ws->inotify_fd < 0) {
 		perror("peachwm config: inotify_init1");
 		free(ws);
-		return NULL;
+		return nullptr;
 	}
 
 	ws->watch_fd = inotify_add_watch(ws->inotify_fd, path,
@@ -822,7 +822,7 @@ config_watch_start(struct wl_event_loop *loop, const char *path,
 		perror("peachwm config: inotify_add_watch");
 		close(ws->inotify_fd);
 		free(ws);
-		return NULL;
+		return nullptr;
 	}
 
 	strncpy(ws->path, path, sizeof(ws->path) - 1);
@@ -840,7 +840,7 @@ config_watch_start(struct wl_event_loop *loop, const char *path,
 		        "Classic.\n");
 		close(ws->inotify_fd);
 		free(ws);
-		return NULL;
+		return nullptr;
 	}
 
 	ws->event_src = src;

parser/parser.h

@@ -2,7 +2,6 @@
 #define PEACHWM_PARSER_H
 
 #include <stdint.h>
-#include <stdbool.h>
 #include <wayland-server-core.h>
 
 /* Maximum lengths. Good for the soul, they say */

src/client.c

@@ -52,8 +52,8 @@ toplevel_from_wlr_surface(struct wlr_surface *s, Client **pc, LayerSurface **pl)
 	struct wlr_xdg_surface *xdg_surface, *tmp_xdg_surface;
 	struct wlr_surface *root_surface;
 	struct wlr_layer_surface_v1 *layer_surface;
-	Client *c = NULL;
+	Client *c = nullptr;
-	LayerSurface *l = NULL;
+	LayerSurface *l = nullptr;
 	int type = -1;
 #ifdef XWAYLAND
 	struct wlr_xwayland_surface *xsurface;
@@ -79,7 +79,7 @@ toplevel_from_wlr_surface(struct wlr_surface *s, Client **pc, LayerSurface **pl)
 
 	xdg_surface = wlr_xdg_surface_try_from_wlr_surface(root_surface);
 	while (xdg_surface) {
-		tmp_xdg_surface = NULL;
+		tmp_xdg_surface = nullptr;
 		switch (xdg_surface->role) {
 		case WLR_XDG_SURFACE_ROLE_POPUP:
 			if (!xdg_surface->popup || !xdg_surface->popup->parent)
@@ -189,16 +189,16 @@ client_get_geometry(Client *c, struct wlr_box *geom)
 Client *
 client_get_parent(Client *c)
 {
-	Client *p = NULL;
+	Client *p = nullptr;
 #ifdef XWAYLAND
 	if (client_is_x11(c)) {
 		if (c->surface.xwayland->parent)
-			toplevel_from_wlr_surface(c->surface.xwayland->parent->surface, &p, NULL);
+			toplevel_from_wlr_surface(c->surface.xwayland->parent->surface, &p, nullptr);
 		return p;
 	}
 #endif
 	if (c->surface.xdg->toplevel->parent)
-		toplevel_from_wlr_surface(c->surface.xdg->toplevel->parent->base->surface, &p, NULL);
+		toplevel_from_wlr_surface(c->surface.xdg->toplevel->parent->base->surface, &p, nullptr);
 	return p;
 }
 
@@ -283,7 +283,7 @@ client_is_stopped(Client *c)
 		return 0;
 #endif
 
-	wl_client_get_credentials(c->surface.xdg->client->client, &pid, NULL, NULL);
+	wl_client_get_credentials(c->surface.xdg->client->client, &pid, nullptr, nullptr);
 	if (waitid(P_PID, pid, &in, WNOHANG|WCONTINUED|WSTOPPED|WNOWAIT) < 0) {
 		/* This process is not our child process, while is very unlikely that
 		 * it is stopped, in order to do not skip frames, assume that it is. */
@@ -316,7 +316,7 @@ client_notify_enter(struct wlr_surface *s, struct wlr_keyboard *kb)
 		wlr_seat_keyboard_notify_enter(seat, s, kb->keycodes,
 				kb->num_keycodes, &kb->modifiers);
 	else
-		wlr_seat_keyboard_notify_enter(seat, s, NULL, 0, NULL);
+		wlr_seat_keyboard_notify_enter(seat, s, nullptr, 0, nullptr);
 }
 
 void

src/ext_workspace.c

@@ -111,7 +111,7 @@ ext_workspace_cleanupmon(Monitor *m)
 	wlr_ext_workspace_group_handle_v1_output_leave(
 			m->ext_group, m->wlr_output);
 	wlr_ext_workspace_group_handle_v1_destroy(m->ext_group);
-	m->ext_group = NULL;
+	m->ext_group = nullptr;
 }
 
 /* status */
@@ -143,7 +143,7 @@ handle_ext_commit(struct wl_listener *listener, void *data)
 	struct wlr_ext_workspace_v1_request *req;
 
 	wl_list_for_each(req, event->requests, link) {
-		struct ext_workspace *ws = NULL;
+		struct ext_workspace *ws = nullptr;
 		struct ext_workspace *w;
 
 		switch (req->type) {

src/ipc.c

@@ -8,7 +8,7 @@
 #include "util.h"
 
 /* IPC globals */
-struct wl_global *ipc_global = NULL;
+struct wl_global *ipc_global = nullptr;
 struct wl_list ipc_managers; /* IpcManager.link */
 
 /* helpers */
@@ -20,7 +20,7 @@ ipc_output_for_mon(IpcManager *mgr, Monitor *m)
 	wl_list_for_each(o, &mgr->outputs, link)
 		if (o->mon == m)
 			return o;
-	return NULL;
+	return nullptr;
 }
 
 /* Send the full state of monitor m to one IpcOutput resource */
@@ -208,7 +208,7 @@ ipc_manager_handle_get_output(struct wl_client *client, struct wl_resource *reso
 {
 	IpcManager *mgr = wl_resource_get_user_data(resource);
 	struct wlr_output *wlr_out = wlr_output_from_resource(output_resource);
-	Monitor *m = (wlr_out && wlr_out->data) ? wlr_out->data : NULL;
+	Monitor *m = (wlr_out && wlr_out->data) ? wlr_out->data : nullptr;
 
 	IpcOutput *out = ecalloc(1, sizeof(*out));
 	out->mon = m;
@@ -272,5 +272,5 @@ ipc_init(void)
 {
 	wl_list_init(&ipc_managers);
 	ipc_global = wl_global_create(dpy, &zpeachwm_ipc_manager_v2_interface,
-			2, NULL, ipc_bind);
+			2, nullptr, ipc_bind);
 }

src/ipc_socket.c

@@ -111,7 +111,7 @@ json_puts(struct json_writer *w, const char *s)
 	json_raw(w, s, strlen(s));
 }
 
-__attribute__((__format__(__printf__, 2, 3)))
+[[gnu::format(printf, 2, 3)]]
 static void
 json_printf(struct json_writer *w, const char *fmt, ...)
 {
@@ -419,7 +419,7 @@ static void
 ipc_build_output(struct json_writer *w, Monitor *m)
 {
 	struct wlr_output *o = m->wlr_output;
-	struct wlr_output_mode *mode = NULL;
+	struct wlr_output_mode *mode = nullptr;
 	int ti;
 
 	if (o->current_mode)
@@ -737,7 +737,7 @@ ipc_handle_command(struct ipc_client *client, const char *payload,
 {
 	struct json_writer w;
 	int success = 0;
-	char *cmd = NULL;
+	char *cmd = nullptr;
 
 	if (len > 0) {
 		cmd = ecalloc(1, len + 1);
@@ -783,16 +783,16 @@ ipc_handle_command(struct ipc_client *client, const char *payload,
 		} else if (!strcmp(cmd, "floating toggle") ||
 			   !strcmp(cmd, "floating enable") ||
 			   !strcmp(cmd, "floating disable")) {
-			togglefloating(NULL);
+			togglefloating(nullptr);
 			success = 1;
 		} else if (!strcmp(cmd, "fullscreen toggle") ||
 			   !strcmp(cmd, "fullscreen enable") ||
 			   !strcmp(cmd, "fullscreen disable")) {
-			togglefullscreen(NULL);
+			togglefullscreen(nullptr);
 			success = 1;
 		} else if (!strcmp(cmd, "kill") ||
 			   !strcmp(cmd, "close")) {
-			killclient(NULL);
+			killclient(nullptr);
 			success = 1;
 		} else if (!strncmp(cmd, "workspace", 9)) {
 			const char *ws = cmd + 9;
@@ -807,7 +807,7 @@ ipc_handle_command(struct ipc_client *client, const char *payload,
 			}
 		} else if (!strcmp(cmd, "exit") ||
 			   !strcmp(cmd, "quit")) {
-			quit(NULL);
+			quit(nullptr);
 			success = 1;
 		} else if (!strcmp(cmd, "reload")) {
 			do_reload();
@@ -868,7 +868,7 @@ ipc_client_close(struct ipc_client *c)
 	wl_list_remove(&c->link);
 	if (c->src) {
 		wl_event_source_remove(c->src);
-		c->src = NULL;
+		c->src = nullptr;
 	}
 	close(c->fd);
 	free(c->payload);
@@ -1025,7 +1025,7 @@ ipc_handle_accept(int fd, uint32_t mask, void *data)
 	c->payload_size = 0;
 	c->payload_len = 0;
 	c->payload_alloc = 0;
-	c->payload = NULL;
+	c->payload = nullptr;
 	c->subscribed = 0;
 
 	src = wl_event_loop_add_fd(ipc_event_loop, cfd,
@@ -1120,7 +1120,7 @@ ipc_socket_init(void)
 
 	ipc_listen_src = wl_event_loop_add_fd(
 		ipc_event_loop, fd, WL_EVENT_READABLE,
-		ipc_handle_accept, NULL);
+		ipc_handle_accept, nullptr);
 	if (!ipc_listen_src) {
 		wlr_log(WLR_ERROR,
 			"ipc: wl_event_loop_add_fd failed");
@@ -1144,7 +1144,7 @@ ipc_socket_finish(void)
 
 	if (ipc_listen_src) {
 		wl_event_source_remove(ipc_listen_src);
-		ipc_listen_src = NULL;
+		ipc_listen_src = nullptr;
 	}
 	if (ipc_listen_fd >= 0) {
 		close(ipc_listen_fd);

src/layout.c

@@ -29,7 +29,7 @@ void       client_set_suspended(Client *c, int suspended);
  * ================================================================ */
 
 const Layout layouts[] = {
-	{"><>", NULL},
+	{"><>", nullptr},
 	{"[T]", dwindle},
 	{"[M]", master},
 	{"[]",  monocle},
@@ -93,9 +93,9 @@ DwindleNode *
 dwindle_find_leaf(DwindleNode *n, Client *c)
 {
 	if (!n)
-		return NULL;
+		return nullptr;
 	if (!n->is_node)
-		return n->client == c ? n : NULL;
+		return n->client == c ? n : nullptr;
 	DwindleNode *r = dwindle_find_leaf(n->children[0], c);
 	return r ? r : dwindle_find_leaf(n->children[1], c);
 }
@@ -104,7 +104,7 @@ static DwindleNode *
 dwindle_first_leaf(DwindleNode *n)
 {
 	if (!n)
-		return NULL;
+		return nullptr;
 	while (n->is_node)
 		n = n->children[0];
 	return n;
@@ -165,7 +165,7 @@ dwindle_insert(DwindleNode **root, Client *new_c, Client *focused)
 		return;
 	}
 
-	DwindleNode *opening_on = focused ? dwindle_find_leaf(*root, focused) : NULL;
+	DwindleNode *opening_on = focused ? dwindle_find_leaf(*root, focused) : nullptr;
 	if (!opening_on)
 		opening_on = dwindle_first_leaf(*root);
 
@@ -203,7 +203,7 @@ dwindle_remove(DwindleNode **root, Client *c)
 	DwindleNode *parent = leaf->parent;
 	if (!parent) {
 		free(leaf);
-		*root = NULL;
+		*root = nullptr;
 		return;
 	}
 
@@ -329,7 +329,7 @@ dwindle(Monitor *m)
 static void
 master_arrange(Monitor *m, int ti)
 {
-	Client *c, *master_c = NULL;
+	Client *c, *master_c = nullptr;
 	Client *stack[256];
 	int nstack = 0, n = 0;
 
@@ -425,7 +425,7 @@ master_remove_client(Client *c)
 		return;
 	for (int i = 0; i < TAGCOUNT; i++) {
 		if (m->master_master[i] == c)
-			m->master_master[i] = NULL;
+			m->master_master[i] = nullptr;
 	}
 }
 

src/peachwm.c

@@ -496,8 +496,8 @@ void arrange(Monitor *m) {
 
   if (curlayout(m)->arrange)
     curlayout(m)->arrange(m);
-  motionnotify(0, NULL, 0, 0, 0, 0);
+  motionnotify(0, nullptr, 0, 0, 0, 0);
-  checkidleinhibitor(NULL);
+  checkidleinhibitor(nullptr);
 }
 
 static void arrangelayer(Monitor *m, struct wl_list *list, struct wlr_box *usable_area,
@@ -552,7 +552,7 @@ static void arrangelayers(Monitor *m) {
           !l->mapped)
         continue;
       /* Deactivate the focused client. */
-      focusclient(NULL, 0);
+      focusclient(nullptr, 0);
       exclusive_focus = l;
       client_notify_enter(l->layer_surface->surface,
                           wlr_seat_get_keyboard(seat));
@@ -607,7 +607,7 @@ static void buttonpress(struct wl_listener *listener, void *data) {
       break;
 
     /* Change focus if the button was _pressed_ over a client */
-    xytonode(cursor->x, cursor->y, NULL, &c, NULL, NULL, NULL);
+    xytonode(cursor->x, cursor->y, nullptr, &c, nullptr, nullptr, nullptr);
     if (c && (!client_is_unmanaged(c) || client_wants_focus(c)))
       focusclient(c, 1);
 
@@ -627,21 +627,21 @@ static void buttonpress(struct wl_listener *listener, void *data) {
       wlr_cursor_set_xcursor(cursor, cursor_mgr, "default");
       if (cursor_mode == CurTileDrag) {
         /* Find whatever tiled client is under the cursor and swap. */
-        Client *target = NULL;
+        Client *target = nullptr;
-        xytonode(cursor->x, cursor->y, NULL, &target, NULL, NULL, NULL);
+        xytonode(cursor->x, cursor->y, nullptr, &target, nullptr, nullptr, nullptr);
         if (target && target != grabc && !target->isfloating &&
             !target->isfullscreen &&
             curlayout(target->mon)->arrange)
           swaptiled(grabc, target);
         cursor_mode = CurNormal;
-        grabc = NULL;
+        grabc = nullptr;
         return;
       }
       cursor_mode = CurNormal;
       /* Drop the window off on its new monitor */
       selmon = xytomon(cursor->x, cursor->y);
       setmon(grabc, selmon, 0);
-      grabc = NULL;
+      grabc = nullptr;
       return;
     }
     cursor_mode = CurNormal;
@@ -682,7 +682,7 @@ static void checkidleinhibitor(struct wlr_surface *exclude) {
 
 static void cleanup(void) {
   config_watch_stop(cfg_watch_src);
-  cfg_watch_src = NULL;
+  cfg_watch_src = nullptr;
   ipc_socket_finish();
   cleanuplisteners();
 
@@ -692,7 +692,7 @@ static void cleanup(void) {
   if (xwayland && xwayland->server && xwayland->server->pid > 0)
     kill(xwayland->server->pid, SIGKILL);
   wlr_xwayland_destroy(xwayland);
-  xwayland = NULL;
+  xwayland = nullptr;
 #endif
 
   wl_display_destroy_clients(dpy);
@@ -702,18 +702,18 @@ static void cleanup(void) {
     struct timespec ts = {.tv_sec = 0, .tv_nsec = 100000000};
     int ret;
     for (int i = 0; i < 50; i++) {
-      ret = waitpid(child_pid, NULL, WNOHANG);
+      ret = waitpid(child_pid, nullptr, WNOHANG);
       if (ret == child_pid || ret == -1)
         goto child_done;
-      nanosleep(&ts, NULL);
+      nanosleep(&ts, nullptr);
     }
     kill(-child_pid, SIGKILL);
-    waitpid(child_pid, NULL, 0);
+    waitpid(child_pid, nullptr, 0);
   }
 child_done:
   wlr_xcursor_manager_destroy(cursor_mgr);
 
-  destroykeyboardgroup(&kb_group->destroy, NULL);
+  destroykeyboardgroup(&kb_group->destroy, nullptr);
 
   /* If it's not destroyed manually, it will cause a use-after-free of wlr_seat.
    * Destroy it until it's fixed on the wlroots side */
@@ -741,8 +741,8 @@ static void cleanupmon(struct wl_listener *listener, void *data) {
   wl_list_remove(&m->link);
   wl_list_remove(&m->request_state.link);
   if (m->lock_surface)
-    destroylocksurface(&m->destroy_lock_surface, NULL);
+    destroylocksurface(&m->destroy_lock_surface, nullptr);
-  m->wlr_output->data = NULL;
+  m->wlr_output->data = nullptr;
   wlr_output_layout_remove(output_layout, m->wlr_output);
   wlr_scene_output_destroy(m->scene_output);
 
@@ -751,7 +751,7 @@ static void cleanupmon(struct wl_listener *listener, void *data) {
   ipc_socket_send_output_event();
   for (int i = 0; i < TAGCOUNT; i++) {
     dwindle_free_tree(m->dwindle_root[i]);
-    m->dwindle_root[i] = NULL;
+    m->dwindle_root[i] = nullptr;
   }
   wlr_scene_node_destroy(&m->fullscreen_bg->node);
   free(m);
@@ -798,14 +798,14 @@ static void closemon(Monitor *m) {
   Client *c;
   int i = 0, nmons = wl_list_length(&mons);
   if (!nmons) {
-    selmon = NULL;
+    selmon = nullptr;
   } else if (m == selmon) {
     do /* don't switch to disabled mons */
       selmon = wl_container_of(mons.next, selmon, link);
     while (!selmon->wlr_output->enabled && i++ < nmons);
 
     if (!selmon->wlr_output->enabled)
-      selmon = NULL;
+      selmon = nullptr;
   }
 
   wl_list_for_each(c, &clients, link) {
@@ -878,7 +878,7 @@ static void commitnotify(struct wl_listener *listener, void *data) {
     if (c->mon) {
       client_set_scale(client_surface(c), c->mon->wlr_output->scale);
     }
-    setmon(c, NULL, 0); /* Make sure to reapply rules in mapnotify() */
+    setmon(c, nullptr, 0); /* Make sure to reapply rules in mapnotify() */
 
     wlr_xdg_toplevel_set_wm_capabilities(
         c->surface.xdg->toplevel, WLR_XDG_TOPLEVEL_WM_CAPABILITIES_FULLSCREEN);
@@ -898,8 +898,8 @@ static void commitnotify(struct wl_listener *listener, void *data) {
 static void commitpopup(struct wl_listener *listener, void *data) {
   struct wlr_surface *surface = data;
   struct wlr_xdg_popup *popup = wlr_xdg_popup_try_from_wlr_surface(surface);
-  LayerSurface *l = NULL;
+  LayerSurface *l = nullptr;
-  Client *c = NULL;
+  Client *c = nullptr;
   struct wlr_box box;
   int type = -1;
 
@@ -939,7 +939,7 @@ static void createidleinhibitor(struct wl_listener *listener, void *data) {
   struct wlr_idle_inhibitor_v1 *idle_inhibitor = data;
   LISTEN_STATIC(&idle_inhibitor->events.destroy, destroyidleinhibitor);
 
-  checkidleinhibitor(NULL);
+  checkidleinhibitor(nullptr);
 }
 
 static void createkeyboard(struct wlr_keyboard *keyboard) {
@@ -961,7 +961,7 @@ static KeyboardGroup *createkeyboardgroup(void) {
   /* Prepare an XKB keymap and assign it to the keyboard group. */
   context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
   if (!(keymap = xkb_keymap_new_from_names(
-            context, &(struct xkb_rule_names){.options = NULL},
+            context, &(struct xkb_rule_names){.options = nullptr},
             XKB_KEYMAP_COMPILE_NO_FLAGS)))
     die("failed to compile keymap");
 
@@ -997,7 +997,7 @@ static void createlayersurface(struct wl_listener *listener, void *data) {
       layers[layermap[layer_surface->pending.layer]];
 
   if (!layer_surface->output &&
-      !(layer_surface->output = selmon ? selmon->wlr_output : NULL)) {
+      !(layer_surface->output = selmon ? selmon->wlr_output : nullptr)) {
     wlr_layer_surface_v1_destroy(layer_surface);
     return;
   }
@@ -1162,7 +1162,7 @@ static void createnotify(struct wl_listener *listener, void *data) {
   /* This event is raised when a client creates a new toplevel (application
    * window). */
   struct wlr_xdg_toplevel *toplevel = data;
-  Client *c = NULL;
+  Client *c = nullptr;
 
   /* Allocate a Client for this surface */
   c = toplevel->base->data = ecalloc(1, sizeof(*c));
@@ -1281,13 +1281,13 @@ static void cursorframe(struct wl_listener *listener, void *data) {
 static void cursorwarptohint(void) {
   if (!active_constraint)
     return;
-  Client *c = NULL;
+  Client *c = nullptr;
   double sx = active_constraint->current.cursor_hint.x;
   double sy = active_constraint->current.cursor_hint.y;
 
-  toplevel_from_wlr_surface(active_constraint->surface, &c, NULL);
+  toplevel_from_wlr_surface(active_constraint->surface, &c, nullptr);
   if (c && active_constraint->current.cursor_hint.enabled) {
-    wlr_cursor_warp(cursor, NULL, sx + c->geom.x + c->bw,
+    wlr_cursor_warp(cursor, nullptr, sx + c->geom.x + c->bw,
                     sy + c->geom.y + c->bw);
     wlr_seat_pointer_warp(active_constraint->seat, sx, sy);
   }
@@ -1303,7 +1303,7 @@ static void destroydecoration(struct wl_listener *listener, void *data) {
 static void destroydragicon(struct wl_listener *listener, void *data) {
   /* Focus enter isn't sent during drag, so refocus the focused node. */
   focusclient(focustop(selmon), 1);
-  motionnotify(0, NULL, 0, 0, 0, 0);
+  motionnotify(0, nullptr, 0, 0, 0, 0);
   wl_list_remove(&listener->link);
   free(listener);
 }
@@ -1336,7 +1336,7 @@ static void destroylock(SessionLock *lock, int unlock) {
   wlr_scene_node_set_enabled(&locked_bg->node, 0);
 
   focusclient(focustop(selmon), 0);
-  motionnotify(0, NULL, 0, 0, 0, 0);
+  motionnotify(0, nullptr, 0, 0, 0, 0);
 
 destroy:
   wl_list_remove(&lock->new_surface.link);
@@ -1344,7 +1344,7 @@ destroy:
   wl_list_remove(&lock->destroy.link);
 
   wlr_scene_node_destroy(&lock->scene->node);
-  cur_lock = NULL;
+  cur_lock = nullptr;
   free(lock);
 }
 
@@ -1352,7 +1352,7 @@ static void destroylocksurface(struct wl_listener *listener, void *data) {
   Monitor *m = wl_container_of(listener, m, destroy_lock_surface);
   struct wlr_session_lock_surface_v1 *surface, *lock_surface = m->lock_surface;
 
-  m->lock_surface = NULL;
+  m->lock_surface = nullptr;
   wl_list_remove(&m->destroy_lock_surface.link);
 
   if (lock_surface->surface != seat->keyboard_state.focused_surface)
@@ -1398,7 +1398,7 @@ static void destroypointerconstraint(struct wl_listener *listener, void *data) {
 
   if (active_constraint == pointer_constraint->constraint) {
     cursorwarptohint();
-    active_constraint = NULL;
+    active_constraint = nullptr;
   }
 
   wl_list_remove(&pointer_constraint->destroy.link);
@@ -1439,8 +1439,8 @@ static bool warp_focus = true;
 void focusclient(Client *c, int lift) {
   struct wlr_surface *old = seat->keyboard_state.focused_surface;
   int unused_lx, unused_ly, old_client_type;
-  Client *old_c = NULL;
+  Client *old_c = nullptr;
-  LayerSurface *old_l = NULL;
+  LayerSurface *old_l = nullptr;
 
   if (locked)
     return;
@@ -1505,7 +1505,7 @@ void focusclient(Client *c, int lift) {
   }
 
   /* Change cursor surface */
-  motionnotify(0, NULL, 0, 0, 0, 0);
+  motionnotify(0, nullptr, 0, 0, 0, 0);
 
   /* Have a client, so focus its top-level wlr_surface */
   client_notify_enter(client_surface(c), wlr_seat_get_keyboard(seat));
@@ -1514,7 +1514,7 @@ void focusclient(Client *c, int lift) {
   client_activate_surface(client_surface(c), 1);
 
   if (cfg.sloppyfocus && warp_focus)
-    wlr_cursor_warp(cursor, NULL, c->geom.x + c->geom.width / 2,
+    wlr_cursor_warp(cursor, nullptr, c->geom.x + c->geom.width / 2,
         c->geom.y + c->geom.height / 2);
 }
 
@@ -1541,7 +1541,7 @@ static void client_center(Client *c, int *cx, int *cy) {
  *
  * In monocle layout, this cycles through clients instead. */
 void focusdir(const Arg *arg) {
-  Client *c, *best = NULL;
+  Client *c, *best = nullptr;
   Client *sel = focustop(selmon);
   int sx, sy, cx, cy;
   double bestdist = 1e18, dist;
@@ -1557,7 +1557,7 @@ void focusdir(const Arg *arg) {
 
   /* In monocle layout, cycle through clients in order */
   if (curlayout(selmon)->arrange == monocle) {
-    Client *first = NULL, *next = NULL, *prev = NULL;
+    Client *first = nullptr, *next = nullptr, *prev = nullptr;
     int found = 0;
 
     wl_list_for_each(c, &clients, link) {
@@ -1652,7 +1652,7 @@ Client *focustop(Monitor *m) {
     if (VISIBLEON(c, m))
       return c;
   }
-  return NULL;
+  return nullptr;
 }
 
 static void fullscreennotify(struct wl_listener *listener, void *data) {
@@ -1685,10 +1685,10 @@ static void gpureset(struct wl_listener *listener, void *data) {
 
 static void handlesig(int signo) {
   if (signo == SIGCHLD)
-    while (waitpid(-1, NULL, WNOHANG) > 0)
+    while (waitpid(-1, nullptr, WNOHANG) > 0)
       ;
   else if (signo == SIGINT || signo == SIGTERM)
-    quit(NULL);
+    quit(nullptr);
 }
 
 static void inputdevice(struct wl_listener *listener, void *data) {
@@ -1727,7 +1727,7 @@ static void inputdevice(struct wl_listener *listener, void *data) {
 static void dispatch_action(const char *action,
                             const char (*args)[CFG_MAX_STRLEN], int nargs) {
   Arg arg = {0};
-  const char *a0 = nargs > 0 ? args[0] : NULL;
+  const char *a0 = nargs > 0 ? args[0] : nullptr;
 
   if (!strcmp(action, "spawn")) {
     /* Build a NULL-terminated argv on the stack.
@@ -1736,29 +1736,29 @@ static void dispatch_action(const char *action,
     int i;
     for (i = 0; i < nargs && i < CFG_MAX_ARGS; i++)
       argv[i] = args[i];
-    argv[i] = NULL;
+    argv[i] = nullptr;
     arg.v = argv;
     spawn(&arg);
     return;
   }
   if (!strcmp(action, "killclient")) {
-    killclient(NULL);
+    killclient(nullptr);
     return;
   }
   if (!strcmp(action, "togglefloating")) {
-    togglefloating(NULL);
+    togglefloating(nullptr);
     return;
   }
   if (!strcmp(action, "togglefullscreen")) {
-    togglefullscreen(NULL);
+    togglefullscreen(nullptr);
     return;
   }
   if (!strcmp(action, "togglegaps")) {
-    togglegaps(NULL);
+    togglegaps(nullptr);
     return;
   }
   if (!strcmp(action, "quit")) {
-    quit(NULL);
+    quit(nullptr);
     return;
   }
 
@@ -1895,11 +1895,11 @@ static void dispatch_action(const char *action,
     return;
   }
   if (!strcmp(action, "togglescratchpad")) {
-    togglescratchpad(NULL);
+    togglescratchpad(nullptr);
     return;
   }
   if (!strcmp(action, "swapdirscratchpad")) {
-    swapdirscratchpad(NULL);
+    swapdirscratchpad(nullptr);
     return;
   }
 
@@ -2045,7 +2045,7 @@ static void locksession(struct wl_listener *listener, void *data) {
     return;
   }
   lock = session_lock->data = ecalloc(1, sizeof(*lock));
-  focusclient(NULL, 0);
+  focusclient(nullptr, 0);
 
   lock->scene = wlr_scene_tree_create(layers[LyrBlock]);
   cur_lock = lock->lock = session_lock;
@@ -2061,7 +2061,7 @@ static void locksession(struct wl_listener *listener, void *data) {
 
 static void mapnotify(struct wl_listener *listener, void *data) {
   /* Called when the surface is mapped, or ready to display on-screen. */
-  Client *p = NULL;
+  Client *p = nullptr;
   Client *w, *c = wl_container_of(listener, c, map);
   Monitor *m;
   int i;
@@ -2188,13 +2188,13 @@ static void motionabsolute(struct wl_listener *listener, void *data) {
 static void motionnotify(uint32_t time, struct wlr_input_device *device, double dx,
                   double dy, double dx_unaccel, double dy_unaccel) {
   double sx = 0, sy = 0, sx_confined, sy_confined;
-  Client *c = NULL, *w = NULL;
+  Client *c = nullptr, *w = nullptr;
-  LayerSurface *l = NULL;
+  LayerSurface *l = nullptr;
-  struct wlr_surface *surface = NULL;
+  struct wlr_surface *surface = nullptr;
   struct wlr_pointer_constraint_v1 *constraint;
 
   /* Find the client under the pointer and send the event along. */
-  xytonode(cursor->x, cursor->y, &surface, &c, NULL, &sx, &sy);
+  xytonode(cursor->x, cursor->y, &surface, &c, nullptr, &sx, &sy);
 
   if (cursor_mode == CurPressed && !seat->drag &&
       surface != seat->pointer_state.focused_surface &&
@@ -2217,7 +2217,7 @@ static void motionnotify(uint32_t time, struct wlr_input_device *device, double
 
     if (active_constraint && cursor_mode != CurResize &&
         cursor_mode != CurMove) {
-      toplevel_from_wlr_surface(active_constraint->surface, &c, NULL);
+      toplevel_from_wlr_surface(active_constraint->surface, &c, nullptr);
       if (c &&
           active_constraint->surface == seat->pointer_state.focused_surface) {
         sx = cursor->x - c->geom.x - c->bw;
@@ -2290,7 +2290,7 @@ static void motionrelative(struct wl_listener *listener, void *data) {
 static void moveresize(const Arg *arg) {
   if (cursor_mode != CurNormal && cursor_mode != CurPressed)
     return;
-  xytonode(cursor->x, cursor->y, NULL, &grabc, NULL, NULL, NULL);
+  xytonode(cursor->x, cursor->y, nullptr, &grabc, nullptr, nullptr, nullptr);
   if (!grabc || client_is_unmanaged(grabc) || grabc->isfullscreen)
     return;
 
@@ -2314,7 +2314,7 @@ static void moveresize(const Arg *arg) {
   case CurResize:
     /* Doesn't work for X11 output - the next absolute motion event
      * returns the cursor to where it started */
-    wlr_cursor_warp_closest(cursor, NULL, grabc->geom.x + grabc->geom.width,
+    wlr_cursor_warp_closest(cursor, nullptr, grabc->geom.x + grabc->geom.width,
                             grabc->geom.y + grabc->geom.height);
     wlr_cursor_set_xcursor(cursor, cursor_mgr, "se-resize");
     break;
@@ -2385,7 +2385,7 @@ static void outputmgrapplyortest(struct wlr_output_configuration_v1 *config,
     wlr_output_configuration_v1_send_failed(config);
   wlr_output_configuration_v1_destroy(config);
 
-  updatemons(NULL, NULL);
+  updatemons(nullptr, nullptr);
 }
 
 static void outputmgrtest(struct wl_listener *listener, void *data) {
@@ -2423,7 +2423,7 @@ static void pointerfocus(Client *c, struct wlr_surface *surface, double sx, doub
 }
 
 void printstatus(void) {
-  Monitor *m = NULL;
+  Monitor *m = nullptr;
   Client *c;
   uint32_t occ, urg, sel;
 
@@ -2475,7 +2475,7 @@ static void powermgrsetmode(struct wl_listener *listener, void *data) {
   wlr_output_commit_state(m->wlr_output, &state);
 
   m->asleep = !event->mode;
-  updatemons(NULL, NULL);
+  updatemons(nullptr, nullptr);
 }
 
 void quit(const Arg *arg) { wl_display_terminate(dpy); }
@@ -2496,7 +2496,7 @@ static void rendermon(struct wl_listener *listener, void *data) {
       goto skip;
   }
 
-  wlr_scene_output_commit(m->scene_output, NULL);
+  wlr_scene_output_commit(m->scene_output, nullptr);
 
 skip:
   /* Let clients know a frame has been rendered */
@@ -2524,7 +2524,7 @@ static void requeststartdrag(struct wl_listener *listener, void *data) {
 static void requestmonstate(struct wl_listener *listener, void *data) {
   struct wlr_output_event_request_state *event = data;
   wlr_output_commit_state(event->output, event->state);
-  updatemons(NULL, NULL);
+  updatemons(nullptr, nullptr);
 }
 
 void resize(Client *c, struct wlr_box geo, int interact) {
@@ -2584,7 +2584,7 @@ static void run(char *startup_cmd) {
       dup2(piperw[0], STDIN_FILENO);
       close(piperw[0]);
       close(piperw[1]);
-      execl("/bin/sh", "/bin/sh", "-c", startup_cmd, NULL);
+      execl("/bin/sh", "/bin/sh", "-c", startup_cmd, nullptr);
       die("startup: execl:");
     }
     dup2(piperw[1], STDOUT_FILENO);
@@ -2610,7 +2610,7 @@ static void run(char *startup_cmd) {
    * cursor position, and set default cursor image */
   selmon = xytomon(cursor->x, cursor->y);
 
-  wlr_cursor_warp_closest(cursor, NULL, cursor->x, cursor->y);
+  wlr_cursor_warp_closest(cursor, nullptr, cursor->x, cursor->y);
   wlr_cursor_set_xcursor(cursor, cursor_mgr, "default");
 
   /* Run the Wayland event loop. This does not return until you exit the
@@ -2717,7 +2717,7 @@ static void setlayout(const Arg *arg) {
     if (sel && VISIBLEON(sel, selmon) && !sel->isfloating && !sel->isfullscreen)
       selmon->master_master[ti] = sel;
     else
-      selmon->master_master[ti] = NULL;
+      selmon->master_master[ti] = nullptr;
     /* Convert to floating: float all tiled clients */
   } else if (!curlayout(selmon)->arrange) {
     Client *c;
@@ -2998,7 +2998,7 @@ static void setup(void) {
   sigemptyset(&sa.sa_mask);
 
   for (i = 0; i < (int)LENGTH(sig); i++)
-    sigaction(sig[i], &sa, NULL);
+    sigaction(sig[i], &sa, nullptr);
 
   /* Load config before anything else so all settings are ready */
   {
@@ -3020,7 +3020,7 @@ static void setup(void) {
     config_path[sizeof(config_path) - 1] = '\0';
   }
 
-  wlr_log_init(cfg.log_level, NULL);
+  wlr_log_init(cfg.log_level, nullptr);
 
   /* The Wayland display is managed by libwayland. It handles accepting
    * clients from the Unix socket, managing Wayland globals, and so on and so
@@ -3041,7 +3041,7 @@ static void setup(void) {
       path = cfgpath;
     }
     cfg_watch_src =
-        config_watch_start(event_loop, path, on_config_reload, NULL);
+        config_watch_start(event_loop, path, on_config_reload, nullptr);
   }
 
   /* The backend is a wlroots feature which abstracts the underlying input and
@@ -3187,7 +3187,7 @@ static void setup(void) {
    * Xcursor themes to source cursor images from and makes sure that cursor
    * images are available at all scale factors on the screen (necessary for
    * HiDPI support). Scaled cursors will be loaded with each output. */
-  cursor_mgr = wlr_xcursor_manager_create(NULL, 24);
+  cursor_mgr = wlr_xcursor_manager_create(nullptr, 24);
   setenv("XCURSOR_SIZE", "24", 1);
 
   /*
@@ -3320,7 +3320,7 @@ static void togglegaps(const Arg *arg) {
 /* swapdir is essentially focusdir but swap */
 
 static void swapdir(const Arg *arg) {
-  Client *c, *other = NULL;
+  Client *c, *other = nullptr;
   Client *sel = focustop(selmon);
   int sx, sy, cx, cy;
   double bestdist = 1e18, dist;
@@ -3463,12 +3463,12 @@ static void unmaplayersurfacenotify(struct wl_listener *listener, void *data) {
   l->mapped = 0;
   wlr_scene_node_set_enabled(&l->scene->node, 0);
   if (l == exclusive_focus)
-    exclusive_focus = NULL;
+    exclusive_focus = nullptr;
   if (l->layer_surface->output && (l->mon = l->layer_surface->output->data))
     arrangelayers(l->mon);
   if (l->layer_surface->surface == seat->keyboard_state.focused_surface)
     focusclient(focustop(selmon), 1);
-  motionnotify(0, NULL, 0, 0, 0, 0);
+  motionnotify(0, nullptr, 0, 0, 0, 0);
 }
 
 static void unmapnotify(struct wl_listener *listener, void *data) {
@@ -3476,12 +3476,12 @@ static void unmapnotify(struct wl_listener *listener, void *data) {
   Client *c = wl_container_of(listener, c, unmap);
   if (c == grabc) {
     cursor_mode = CurNormal;
-    grabc = NULL;
+    grabc = nullptr;
   }
 
   if (client_is_unmanaged(c)) {
     if (c == exclusive_focus) {
-      exclusive_focus = NULL;
+      exclusive_focus = nullptr;
       focusclient(focustop(selmon), 1);
     }
   } else {
@@ -3493,9 +3493,9 @@ static void unmapnotify(struct wl_listener *listener, void *data) {
     /* Clear any stale scratchpad references to this client */
     if (oldmon) {
       if (oldmon->scratchpad_current == c)
-        oldmon->scratchpad_current = NULL;
+        oldmon->scratchpad_current = nullptr;
       if (oldmon->scratchpad_prev_focus == c)
-        oldmon->scratchpad_prev_focus = NULL;
+        oldmon->scratchpad_prev_focus = nullptr;
     }
     if (c->isscratchpad && oldmon && oldmon->scratchpad_visible) {
       /* Closing a scratchpad client: focus another scratchpad client */
@@ -3510,17 +3510,17 @@ static void unmapnotify(struct wl_listener *listener, void *data) {
       }
       if (!found)
         focusclient(focustop(selmon), 1);
-      c->mon = NULL;
+      c->mon = nullptr;
       arrange(oldmon);
     } else {
-      setmon(c, NULL, 0);
+      setmon(c, nullptr, 0);
     }
   }
 
   wlr_scene_node_destroy(&c->scene->node);
   printstatus();
   ipc_socket_send_window_event("close");
-  motionnotify(0, NULL, 0, 0, 0, 0);
+  motionnotify(0, nullptr, 0, 0, 0, 0);
 }
 
 static void updatemons(struct wl_listener *listener, void *data) {
@@ -3557,7 +3557,7 @@ static void updatemons(struct wl_listener *listener, void *data) {
   }
 
   /* Now that we update the output layout we can get its box */
-  wlr_output_layout_get_box(output_layout, NULL, &sgeom);
+  wlr_output_layout_get_box(output_layout, nullptr, &sgeom);
 
   wlr_scene_node_set_position(&root_bg->node, sgeom.x, sgeom.y);
   wlr_scene_rect_set_size(root_bg, sgeom.width, sgeom.height);
@@ -3616,7 +3616,7 @@ static void updatemons(struct wl_listener *listener, void *data) {
     }
   }
 
-  wlr_cursor_move(cursor, NULL, 0, 0);
+  wlr_cursor_move(cursor, nullptr, 0, 0);
 
   wlr_output_manager_v1_set_configuration(output_mgr, config);
 }
@@ -3631,8 +3631,8 @@ static void updatetitle(struct wl_listener *listener, void *data) {
 
 static void urgent(struct wl_listener *listener, void *data) {
   struct wlr_xdg_activation_v1_request_activate_event *event = data;
-  Client *c = NULL;
+  Client *c = nullptr;
-  toplevel_from_wlr_surface(event->surface, &c, NULL);
+  toplevel_from_wlr_surface(event->surface, &c, nullptr);
   if (!c || c == focustop(selmon))
     return;
 
@@ -3678,15 +3678,15 @@ static void virtualpointer(struct wl_listener *listener, void *data) {
 
 Monitor *xytomon(double x, double y) {
   struct wlr_output *o = wlr_output_layout_output_at(output_layout, x, y);
-  return o ? o->data : NULL;
+  return o ? o->data : nullptr;
 }
 
 static void xytonode(double x, double y, struct wlr_surface **psurface, Client **pc,
               LayerSurface **pl, double *nx, double *ny) {
   struct wlr_scene_node *node, *pnode;
-  struct wlr_surface *surface = NULL;
+  struct wlr_surface *surface = nullptr;
-  Client *c = NULL;
+  Client *c = nullptr;
-  LayerSurface *l = NULL;
+  LayerSurface *l = nullptr;
   int layer;
 
   for (layer = NUM_LAYERS - 1; !surface && layer >= 0; layer--) {
@@ -3701,7 +3701,7 @@ static void xytonode(double x, double y, struct wlr_surface **psurface, Client *
     for (pnode = node; pnode && !c; pnode = &pnode->parent->node)
       c = pnode->data;
     if (c && c->type == LayerShell) {
-      c = NULL;
+      c = nullptr;
       l = pnode->data;
     }
   }
@@ -3816,7 +3816,7 @@ static void xwaylandready(struct wl_listener *listener, void *data) {
 // ── main() ──────────────────────────────────────────────────
 
 int main(int argc, char *argv[]) {
-  char *startup_cmd = NULL;
+  char *startup_cmd = nullptr;
   int c;
 
   while ((c = getopt(argc, argv, "c:s:hdv")) != -1) {

src/scratchpad.c

@@ -53,7 +53,7 @@ void scratchpad_arrange(Monitor *m) {
 
 void togglescratchpad(const Arg *arg) {
 	Monitor *m = selmon;
-	Client *c, *focus = NULL;
+	Client *c, *focus = nullptr;
 
 	if (!m)
 		return;
@@ -92,7 +92,7 @@ void togglescratchpad(const Arg *arg) {
 				client_set_suspended(c, 1);
 			}
 		}
-		m->scratchpad_current = NULL;
+		m->scratchpad_current = nullptr;
 		/* Restore focus to previous client */
 		if (m->scratchpad_prev_focus && VISIBLEON(m->scratchpad_prev_focus, m))
 			focusclient(m->scratchpad_prev_focus, 1);
@@ -114,7 +114,7 @@ void swapdirscratchpad(const Arg *arg) {
 
 	if (sel->isscratchpad) {
 		/* Move FROM scratchpad to current workspace */
-		Client *next = NULL;
+		Client *next = nullptr;
 		sel->isscratchpad = 0;
 		sel->isfloating = 0;
 		sel->tags = selmon->tagset[selmon->seltags];
@@ -127,11 +127,11 @@ void swapdirscratchpad(const Arg *arg) {
 				}
 			}
 			if (!next)
-				selmon->scratchpad_current = NULL;
+				selmon->scratchpad_current = nullptr;
 			else
 				selmon->scratchpad_current = next;
 		} else {
-			selmon->scratchpad_current = NULL;
+			selmon->scratchpad_current = nullptr;
 		}
 		/* setfloating reparents + arranges; let it manage visibility */
 		setfloating(sel, 0);
@@ -177,7 +177,7 @@ void swapdirscratchpad(const Arg *arg) {
 
 void scratchpad_focusdir_cycle(const Arg *arg) {
 	Client *sel = focustop(selmon);
-	Client *c, *first = NULL, *next = NULL, *prev = NULL;
+	Client *c, *first = nullptr, *next = nullptr, *prev = nullptr;
 	int found = 0;
 
 	wl_list_for_each(c, &clients, link) {
@@ -196,7 +196,7 @@ void scratchpad_focusdir_cycle(const Arg *arg) {
 		prev = c;
 	}
 
-	Client *target = NULL;
+	Client *target = nullptr;
 	if (arg->i == WLR_DIRECTION_DOWN || arg->i == WLR_DIRECTION_RIGHT) {
 		if (next)
 			target = next;

src/util.c

@@ -7,7 +7,7 @@
 
 #include "util.h"
 
-_Noreturn void
+[[noreturn]] void
 die(const char *fmt, ...) {
 	va_list ap;
 
@@ -17,7 +17,7 @@ die(const char *fmt, ...) {
 
 	if (fmt[0] && fmt[strlen(fmt)-1] == ':') {
 		fputc(' ', stderr);
-		perror(NULL);
+		perror(nullptr);
 	} else {
 		fputc('\n', stderr);
 	}

src/util.h

@@ -2,6 +2,6 @@
 
 #include <stddef.h>
 
-_Noreturn void die(const char *fmt, ...);
+[[noreturn]] void die(const char *fmt, ...);
 void *ecalloc(size_t nmemb, size_t size);
 int fd_set_nonblock(int fd);

src/wlr_ext_workspace_v1.c

@@ -202,7 +202,7 @@ static void destroy_workspace_resource(
 	struct wlr_ext_workspace_v1_resource *workspace_res) {
 	wl_list_remove(&workspace_res->link);
 	wl_list_remove(&workspace_res->manager_resource_link);
-	wl_resource_set_user_data(workspace_res->resource, NULL);
+	wl_resource_set_user_data(workspace_res->resource, nullptr);
 	free(workspace_res);
 }
 
@@ -220,7 +220,7 @@ static struct wlr_ext_workspace_v1_resource *create_workspace_resource(
 	struct wlr_ext_workspace_v1_resource *workspace_res =
 		calloc(1, sizeof(*workspace_res));
 	if (!workspace_res) {
-		return NULL;
+		return nullptr;
 	}
 
 	struct wl_client *client = wl_resource_get_client(manager_res->resource);
@@ -229,7 +229,7 @@ static struct wlr_ext_workspace_v1_resource *create_workspace_resource(
 						   wl_resource_get_version(manager_res->resource), 0);
 	if (!workspace_res->resource) {
 		free(workspace_res);
-		return NULL;
+		return nullptr;
 	}
 	wl_resource_set_implementation(workspace_res->resource, &workspace_impl,
 								   workspace_res, workspace_resource_destroy);
@@ -247,7 +247,7 @@ static void
 destroy_group_resource(struct wlr_ext_workspace_group_v1_resource *group_res) {
 	wl_list_remove(&group_res->link);
 	wl_list_remove(&group_res->manager_resource_link);
-	wl_resource_set_user_data(group_res->resource, NULL);
+	wl_resource_set_user_data(group_res->resource, nullptr);
 	free(group_res);
 }
 
@@ -265,16 +265,16 @@ static struct wlr_ext_workspace_group_v1_resource *create_group_resource(
 	struct wlr_ext_workspace_group_v1_resource *group_res =
 		calloc(1, sizeof(*group_res));
 	if (!group_res) {
-		return NULL;
+		return nullptr;
 	}
 
 	struct wl_client *client = wl_resource_get_client(manager_res->resource);
 	uint32_t version = wl_resource_get_version(manager_res->resource);
 	group_res->resource = wl_resource_create(
 		client, &ext_workspace_group_handle_v1_interface, version, 0);
-	if (group_res->resource == NULL) {
+	if (group_res->resource == nullptr) {
 		free(group_res);
-		return NULL;
+		return nullptr;
 	}
 	wl_resource_set_implementation(group_res->resource, &group_impl, group_res,
 								   group_handle_resource_destroy);
@@ -309,30 +309,30 @@ clear_requests_by(struct wlr_ext_workspace_manager_v1_resource *manager_res,
 		switch (req->type) {
 		case WLR_EXT_WORKSPACE_V1_REQUEST_CREATE_WORKSPACE:
 			if (group && req->create_workspace.group == group) {
-				req->create_workspace.group = NULL;
+				req->create_workspace.group = nullptr;
 			}
 			break;
 		case WLR_EXT_WORKSPACE_V1_REQUEST_ACTIVATE:
 			if (workspace && req->activate.workspace == workspace) {
-				req->activate.workspace = NULL;
+				req->activate.workspace = nullptr;
 			}
 			break;
 		case WLR_EXT_WORKSPACE_V1_REQUEST_DEACTIVATE:
 			if (workspace && req->deactivate.workspace == workspace) {
-				req->deactivate.workspace = NULL;
+				req->deactivate.workspace = nullptr;
 			}
 			break;
 		case WLR_EXT_WORKSPACE_V1_REQUEST_ASSIGN:
 			if (workspace && req->assign.workspace == workspace) {
-				req->assign.workspace = NULL;
+				req->assign.workspace = nullptr;
 			}
 			if (group && req->assign.group == group) {
-				req->assign.group = NULL;
+				req->assign.group = nullptr;
 			}
 			break;
 		case WLR_EXT_WORKSPACE_V1_REQUEST_REMOVE:
 			if (workspace && req->remove.workspace == workspace) {
-				req->remove.workspace = NULL;
+				req->remove.workspace = nullptr;
 			}
 			break;
 		}
@@ -361,7 +361,7 @@ static void handle_idle(void *data) {
 	wl_list_for_each(manager_res, &manager->resources, link) {
 		ext_workspace_manager_v1_send_done(manager_res->resource);
 	}
-	manager->idle_source = NULL;
+	manager->idle_source = nullptr;
 }
 
 static void
@@ -420,7 +420,7 @@ static void destroy_manager_resource(
 	}
 
 	wl_list_remove(&manager_res->link);
-	wl_resource_set_user_data(manager_res->resource, NULL);
+	wl_resource_set_user_data(manager_res->resource, nullptr);
 	free(manager_res);
 }
 
@@ -527,7 +527,7 @@ static void manager_handle_display_destroy(struct wl_listener *listener,
 	struct wlr_ext_workspace_manager_v1 *manager =
 		wl_container_of(listener, manager, display_destroy);
 
-	wl_signal_emit_mutable(&manager->events.destroy, NULL);
+	wl_signal_emit_mutable(&manager->events.destroy, nullptr);
 	assert(wl_list_empty(&manager->events.commit.listener_list));
 	assert(wl_list_empty(&manager->events.destroy.listener_list));
 
@@ -562,7 +562,7 @@ wlr_ext_workspace_manager_v1_create(struct wl_display *display,
 
 	struct wlr_ext_workspace_manager_v1 *manager = calloc(1, sizeof(*manager));
 	if (!manager) {
-		return NULL;
+		return nullptr;
 	}
 
 	manager->global =
@@ -570,7 +570,7 @@ wlr_ext_workspace_manager_v1_create(struct wl_display *display,
 						 manager, manager_bind);
 	if (!manager->global) {
 		free(manager);
-		return NULL;
+		return nullptr;
 	}
 
 	manager->event_loop = wl_display_get_event_loop(display);
@@ -592,7 +592,7 @@ wlr_ext_workspace_group_handle_v1_create(
 	struct wlr_ext_workspace_manager_v1 *manager, uint32_t caps) {
 	struct wlr_ext_workspace_group_handle_v1 *group = calloc(1, sizeof(*group));
 	if (!group) {
-		return NULL;
+		return nullptr;
 	}
 
 	group->manager = manager;
@@ -685,7 +685,7 @@ void wlr_ext_workspace_group_handle_v1_destroy(
 		return;
 	}
 
-	wl_signal_emit_mutable(&group->events.destroy, NULL);
+	wl_signal_emit_mutable(&group->events.destroy, nullptr);
 
 	assert(wl_list_empty(&group->events.destroy.listener_list));
 
@@ -693,7 +693,7 @@ void wlr_ext_workspace_group_handle_v1_destroy(
 	wl_list_for_each(workspace, &group->manager->workspaces, link) {
 		if (workspace->group == group) {
 			workspace_send_group(workspace, group, false);
-			workspace->group = NULL;
+			workspace->group = nullptr;
 		}
 	}
 
@@ -705,7 +705,7 @@ void wlr_ext_workspace_group_handle_v1_destroy(
 
 	struct wlr_ext_workspace_manager_v1_resource *manager_res;
 	wl_list_for_each(manager_res, &group->manager->resources, link) {
-		clear_requests_by(manager_res, group, NULL);
+		clear_requests_by(manager_res, group, nullptr);
 	}
 
 	struct wlr_ext_workspace_v1_group_output *group_output, *tmp3;
@@ -753,7 +753,7 @@ get_group_output(struct wlr_ext_workspace_group_handle_v1 *group,
 			return group_output;
 		}
 	}
-	return NULL;
+	return nullptr;
 }
 
 void wlr_ext_workspace_group_handle_v1_output_enter(
@@ -798,7 +798,7 @@ wlr_ext_workspace_handle_v1_create(struct wlr_ext_workspace_manager_v1 *manager,
 	struct wlr_ext_workspace_handle_v1 *workspace =
 		calloc(1, sizeof(*workspace));
 	if (!workspace) {
-		return NULL;
+		return nullptr;
 	}
 
 	workspace->manager = manager;
@@ -808,7 +808,7 @@ wlr_ext_workspace_handle_v1_create(struct wlr_ext_workspace_manager_v1 *manager,
 		workspace->id = strdup(id);
 		if (!workspace->id) {
 			free(workspace);
-			return NULL;
+			return nullptr;
 		}
 	}
 
@@ -841,7 +841,7 @@ void wlr_ext_workspace_handle_v1_destroy(
 		return;
 	}
 
-	wl_signal_emit_mutable(&workspace->events.destroy, NULL);
+	wl_signal_emit_mutable(&workspace->events.destroy, nullptr);
 
 	assert(wl_list_empty(&workspace->events.destroy.listener_list));
 
@@ -857,7 +857,7 @@ void wlr_ext_workspace_handle_v1_destroy(
 
 	struct wlr_ext_workspace_manager_v1_resource *manager_res;
 	wl_list_for_each(manager_res, &workspace->manager->resources, link) {
-		clear_requests_by(manager_res, NULL, workspace);
+		clear_requests_by(manager_res, nullptr, workspace);
 	}
 
 	manager_schedule_done(workspace->manager);
@@ -895,7 +895,7 @@ void wlr_ext_workspace_handle_v1_set_name(
 
 	free(workspace->name);
 	workspace->name = strdup(name);
-	if (workspace->name == NULL) {
+	if (workspace->name == nullptr) {
 		return;
 	}