Compare pointers to "NULL" instead of "0".

"bad_zero.cocci" spatch from http://coccinelle.lip6.fr/impact_linux.php.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

12 files changed, 93 insertions, 93 deletions

diff --git a/src/apoint.c b/src/apoint.c
index 4b562f7..f612071 100644
--- a/src/apoint.c
+++ b/src/apoint.c
@@ -141,7 +141,7 @@ apoint_new (char *mesg, char *note, long start, long dur, char state)
   i = &alist_p->root;
   for (;;)
     {
-      if (*i == 0 || (*i)->start > start)
+      if (*i == NULL || (*i)->start > start)
         {
           o->next = *i;
           *i = o;
@@ -509,7 +509,7 @@ apoint_delete_bynum (long start, unsigned num, enum eraseflg flag)
   n = 0;
   pthread_mutex_lock (&(alist_p->mutex));
   iptr = &alist_p->root;
-  for (i = alist_p->root; i != 0; i = i->next)
+  for (i = alist_p->root; i != NULL; i = i->next)
     {
       if (apoint_inday (i, start))
         {
@@ -616,7 +616,7 @@ apoint_check_next (struct notify_app *app, long start)
   struct apoint *i;
 
   pthread_mutex_lock (&(alist_p->mutex));
-  for (i = alist_p->root; i != 0; i = i->next)
+  for (i = alist_p->root; i != NULL; i = i->next)
     {
       if (i->start > app->time)
         {
@@ -684,7 +684,7 @@ apoint_switch_notify (void)
   need_chk_notify = 0;
   pthread_mutex_lock (&(alist_p->mutex));
 
-  for (apoint = alist_p->root; apoint != 0; apoint = apoint->next)
+  for (apoint = alist_p->root; apoint != NULL; apoint = apoint->next)
     {
       if (apoint_inday (apoint, date))
         {
diff --git a/src/args.c b/src/args.c
index 4ac2fd5..cd2c5d5 100644
--- a/src/args.c
+++ b/src/args.c
@@ -267,7 +267,7 @@ todo_arg (int priority, int print_note, regex_t *regex)
     print_notefile (stdout, i->note, 1);                                \
   } while (0)
 
-  for (i = todolist; i != 0; i = i->next)
+  for (i = todolist; i != NULL; i = i->next)
     {
       if (regex && regexec (regex, i->mesg, 0, 0, 0) != 0)
         continue;
@@ -370,7 +370,7 @@ app_arg (int add_line, struct date *day, long date, int print_note,
    * that date and it is the first one, and then print all the events for
    * that date.
    */
-  for (re = recur_elist; re != 0; re = re->next)
+  for (re = recur_elist; re != NULL; re = re->next)
     {
       if (recur_item_inday (re->day, re->exc, re->rpt->type, re->rpt->freq,
                             re->rpt->until, today))
@@ -397,7 +397,7 @@ app_arg (int add_line, struct date *day, long date, int print_note,
         }
     }
 
-  for (j = eventlist; j != 0; j = j->next)
+  for (j = eventlist; j != NULL; j = j->next)
     {
       if (event_inday (j, today))
         {
@@ -425,7 +425,7 @@ app_arg (int add_line, struct date *day, long date, int print_note,
 
   /* Same process is performed but this time on the appointments. */
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (ra = recur_alist_p->root; ra != 0; ra = ra->next)
+  for (ra = recur_alist_p->root; ra != NULL; ra = ra->next)
     {
       if (recur_item_inday (ra->start, ra->exc, ra->rpt->type, ra->rpt->freq,
                             ra->rpt->until, today))
@@ -465,7 +465,7 @@ app_arg (int add_line, struct date *day, long date, int print_note,
   pthread_mutex_unlock (&(recur_alist_p->mutex));
 
   pthread_mutex_lock (&(alist_p->mutex));
-  for (i = alist_p->root; i != 0; i = i->next)
+  for (i = alist_p->root; i != NULL; i = i->next)
     {
       if (apoint_inday (i, today))
         {
diff --git a/src/custom.c b/src/custom.c
index 29a6261..e8cf0fe 100644
--- a/src/custom.c
+++ b/src/custom.c
@@ -1243,7 +1243,7 @@ print_keys_bindings (WINDOW *win, int selected_row, int selected_elm, int yoff)
               int pos;
 
               pos = KEYPOS;
-              while ((key = keys_action_nkey (action, noelm)) != 0)
+              while ((key = keys_action_nkey (action, noelm)) != NULL)
                 {
                   if (noelm == selected_elm)
                     print_key_incolor (win, key, y, pos);
diff --git a/src/day.c b/src/day.c
index 8561123..0dc888e 100644
--- a/src/day.c
+++ b/src/day.c
@@ -90,7 +90,7 @@ day_add_event (int type, char *mesg, char *note, long day, int id)
   i = &day_items_ptr;
   for (;;)
     {
-      if (*i == 0)
+      if (*i == NULL)
         {
           o->next = *i;
           *i = o;
@@ -121,7 +121,7 @@ day_add_apoint (int type, char *mesg, char *note, long start, long dur,
   i = &day_items_ptr;
   for (;;)
     {
-      if (*i == 0)
+      if (*i == NULL)
         {
           insert_item = 1;
         }
@@ -153,7 +153,7 @@ day_store_events (long date)
   struct event *j;
   int e_nb = 0;
 
-  for (j = eventlist; j != 0; j = j->next)
+  for (j = eventlist; j != NULL; j = j->next)
     {
       if (event_inday (j, date))
         {
@@ -178,7 +178,7 @@ day_store_recur_events (long date)
   struct recur_event *j;
   int e_nb = 0;
 
-  for (j = recur_elist; j != 0; j = j->next)
+  for (j = recur_elist; j != NULL; j = j->next)
     {
       if (recur_item_inday (j->day, j->exc, j->rpt->type, j->rpt->freq,
                             j->rpt->until, date))
@@ -205,7 +205,7 @@ day_store_apoints (long date)
   int a_nb = 0;
 
   pthread_mutex_lock (&(alist_p->mutex));
-  for (j = alist_p->root; j != 0; j = j->next)
+  for (j = alist_p->root; j != NULL; j = j->next)
     {
       if (apoint_inday (j, date))
         {
@@ -234,7 +234,7 @@ day_store_recur_apoints (long date)
   int a_nb = 0, n = 0;
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (j = recur_alist_p->root; j != 0; j = j->next)
+  for (j = recur_alist_p->root; j != NULL; j = j->next)
     {
       if ((real_start = recur_item_inday (j->start, j->exc,
                                           j->rpt->type, j->rpt->freq,
@@ -266,7 +266,7 @@ day_store_items (long date, unsigned *pnb_events, unsigned *pnb_apoints)
   int nb_events, nb_recur_events;
   int nb_apoints, nb_recur_apoints;
 
-  if (day_items_ptr != 0)
+  if (day_items_ptr != NULL)
     day_free_list ();
   nb_recur_events = day_store_recur_events (date);
   nb_events = day_store_events (date);
@@ -405,7 +405,7 @@ day_write_pad (long date, int width, int length, int incolor)
 
   line = item_number = 0;
 
-  for (p = day_items_ptr; p != 0; p = p->next)
+  for (p = day_items_ptr; p != NULL; p = p->next)
     {
       if (p->type == RECUR_EVNT || p->type == RECUR_APPT)
         recur = 1;
@@ -481,13 +481,13 @@ day_check_if_item (struct date day)
   struct apoint *a;
   const long date = date2sec (day, 0, 0);
 
-  for (re = recur_elist; re != 0; re = re->next)
+  for (re = recur_elist; re != NULL; re = re->next)
     if (recur_item_inday (re->day, re->exc, re->rpt->type,
                           re->rpt->freq, re->rpt->until, date))
       return (1);
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (ra = recur_alist_p->root; ra != 0; ra = ra->next)
+  for (ra = recur_alist_p->root; ra != NULL; ra = ra->next)
     if (recur_item_inday (ra->start, ra->exc, ra->rpt->type,
                           ra->rpt->freq, ra->rpt->until, date))
       {
@@ -496,12 +496,12 @@ day_check_if_item (struct date day)
       }
   pthread_mutex_unlock (&(recur_alist_p->mutex));
 
-  for (e = eventlist; e != 0; e = e->next)
+  for (e = eventlist; e != NULL; e = e->next)
     if (event_inday (e, date))
       return (1);
 
   pthread_mutex_lock (&(alist_p->mutex));
-  for (a = alist_p->root; a != 0; a = a->next)
+  for (a = alist_p->root; a != NULL; a = a->next)
     if (apoint_inday (a, date))
       {
         pthread_mutex_unlock (&(alist_p->mutex));
@@ -547,7 +547,7 @@ day_chk_busy_slices (struct date day, int slicesno, int *slices)
 #define  SLICENUM(tsec)  ((tsec) / slicelen % slicesno)
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (ra = recur_alist_p->root; ra != 0; ra = ra->next)
+  for (ra = recur_alist_p->root; ra != NULL; ra = ra->next)
     if (recur_item_inday (ra->start, ra->exc, ra->rpt->type,
                           ra->rpt->freq, ra->rpt->until, date))
       {
@@ -564,7 +564,7 @@ day_chk_busy_slices (struct date day, int slicesno, int *slices)
   pthread_mutex_unlock (&(recur_alist_p->mutex));
 
   pthread_mutex_lock (&(alist_p->mutex));
-  for (a = alist_p->root; a != 0; a = a->next)
+  for (a = alist_p->root; a != NULL; a = a->next)
     if (apoint_inday (a, date))
       {
         long start, end;
diff --git a/src/event.c b/src/event.c
index fc527c6..a3c4750 100644
--- a/src/event.c
+++ b/src/event.c
@@ -96,7 +96,7 @@ event_new (char *mesg, char *note, long day, int id)
   i = &eventlist;
   for (;;)
     {
-      if (*i == 0 || (*i)->day > day)
+      if (*i == NULL || (*i)->day > day)
         {
           o->next = *i;
           *i = o;
@@ -195,7 +195,7 @@ event_delete_bynum (long start, unsigned num, enum eraseflg flag)
 
   n = 0;
   iptr = &eventlist;
-  for (i = eventlist; i != 0; i = i->next)
+  for (i = eventlist; i != NULL; i = i->next)
     {
       if (event_inday (i, start))
         {
diff --git a/src/io.c b/src/io.c
index 0fe930e..7619696 100644
--- a/src/io.c
+++ b/src/io.c
@@ -346,7 +346,7 @@ ical_export_recur_events (FILE *stream)
   struct days *day;
   char ical_date[BUFSIZ];
 
-  for (i = recur_elist; i != 0; i = i->next)
+  for (i = recur_elist; i != NULL; i = i->next)
     {
       date_sec2date_fmt (i->day, ICALDATEFMT, ical_date);
       (void)fprintf (stream, "BEGIN:VEVENT\n");
@@ -416,7 +416,7 @@ pcal_export_recur_events (FILE *stream)
   (void)fprintf (stream,
                  "# (pcal does not support from..until dates specification\n");
 
-  for (i = recur_elist; i != 0; i = i->next)
+  for (i = recur_elist; i != NULL; i = i->next)
     {
       if (i->rpt->until == 0 && i->rpt->freq == 1)
         {
@@ -464,7 +464,7 @@ ical_export_events (FILE *stream)
   struct event *i;
   char ical_date[BUFSIZ];
 
-  for (i = eventlist; i != 0; i = i->next)
+  for (i = eventlist; i != NULL; i = i->next)
     {
       date_sec2date_fmt (i->day, ICALDATEFMT, ical_date);
       (void)fprintf (stream, "BEGIN:VEVENT\n");
@@ -480,7 +480,7 @@ pcal_export_events (FILE *stream)
   struct event *i;
 
   (void)fprintf (stream, "\n# ======\n# Events\n# ======\n");
-  for (i = eventlist; i != 0; i = i->next)
+  for (i = eventlist; i != NULL; i = i->next)
     pcal_dump_event (stream, i->day, 0, i->mesg);
   (void)fprintf (stream, "\n");
 }
@@ -495,7 +495,7 @@ ical_export_recur_apoints (FILE *stream)
   char ical_date[BUFSIZ];
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (i = recur_alist_p->root; i != 0; i = i->next)
+  for (i = recur_alist_p->root; i != NULL; i = i->next)
     {
       date_sec2date_fmt (i->start, ICALDATETIMEFMT, ical_datetime);
       (void)fprintf (stream, "BEGIN:VEVENT\n");
@@ -544,7 +544,7 @@ pcal_export_recur_apoints (FILE *stream)
   (void)fprintf (stream,
                  "# (pcal does not support from..until dates specification\n");
 
-  for (i = recur_alist_p->root; i != 0; i = i->next)
+  for (i = recur_alist_p->root; i != NULL; i = i->next)
     {
       if (i->rpt->until == 0 && i->rpt->freq == 1)
         {
@@ -598,7 +598,7 @@ ical_export_apoints (FILE *stream)
   char ical_datetime[BUFSIZ];
 
   pthread_mutex_lock (&(alist_p->mutex));
-  for (i = alist_p->root; i != 0; i = i->next)
+  for (i = alist_p->root; i != NULL; i = i->next)
     {
       date_sec2date_fmt (i->start, ICALDATETIMEFMT, ical_datetime);
       (void)fprintf (stream, "BEGIN:VEVENT\n");
@@ -619,7 +619,7 @@ pcal_export_apoints (FILE *stream)
 
   (void)fprintf (stream, "\n# ============\n# Appointments\n# ============\n");
   pthread_mutex_lock (&(alist_p->mutex));
-  for (i = alist_p->root; i != 0; i = i->next)
+  for (i = alist_p->root; i != NULL; i = i->next)
       pcal_dump_apoint (stream, i->start, i->dur, i->mesg);
   pthread_mutex_unlock (&(alist_p->mutex));
   (void)fprintf (stream, "\n");
@@ -631,7 +631,7 @@ ical_export_todo (FILE *stream)
 {
   struct todo *i;
 
-  for (i = todolist; i != 0; i = i->next)
+  for (i = todolist; i != NULL; i = i->next)
     {
       if (i->id < 0)  /* completed items */
         continue;
@@ -649,7 +649,7 @@ pcal_export_todo (FILE *stream)
   struct todo *i;
 
   (void)fprintf (stream, "#\n# Todos\n#\n");
-  for (i = todolist; i != 0; i = i->next)
+  for (i = todolist; i != NULL; i = i->next)
     {
       if (i->id < 0)  /* completed items */
         continue;
@@ -831,7 +831,7 @@ io_save_conf (struct conf *conf)
   char theme_name[BUFSIZ];
   FILE *fp;
 
-  if ((fp = fopen (path_conf, "w")) == 0)
+  if ((fp = fopen (path_conf, "w")) == NULL)
     return 0;
 
   custom_color_theme_name (theme_name);
@@ -963,19 +963,19 @@ io_save_apts (void)
   struct event *e;
   FILE *fp;
 
-  if ((fp = fopen (path_apts, "w")) == 0)
+  if ((fp = fopen (path_apts, "w")) == NULL)
     return 0;
 
   recur_save_data (fp);
 
   if (ui_mode == UI_CURSES)
     pthread_mutex_lock (&(alist_p->mutex));
-  for (a = alist_p->root; a != 0; a = a->next)
+  for (a = alist_p->root; a != NULL; a = a->next)
     apoint_write (a, fp);
   if (ui_mode == UI_CURSES)
     pthread_mutex_unlock (&(alist_p->mutex));
 
-  for (e = eventlist; e != 0; e = e->next)
+  for (e = eventlist; e != NULL; e = e->next)
     event_write (e, fp);
   file_close (fp, __FILE_POS__);
 
@@ -989,10 +989,10 @@ io_save_todo (void)
   struct todo *t;
   FILE *fp;
 
-  if ((fp = fopen (path_todo, "w")) == 0)
+  if ((fp = fopen (path_todo, "w")) == NULL)
     return 0;
 
-  for (t = todolist; t != 0; t = t->next)
+  for (t = todolist; t != NULL; t = t->next)
     {
       if (t->note)
         (void)fprintf (fp, "[%d]>%s %s\n", t->id, t->note, t->mesg);
@@ -1010,7 +1010,7 @@ io_save_keys (void)
 {
   FILE *fp;
 
-  if ((fp = fopen (path_keys, "w")) == 0)
+  if ((fp = fopen (path_keys, "w")) == NULL)
     return 0;
 
   keys_save_bindings (fp);
@@ -1516,7 +1516,7 @@ io_file_exist (char *file)
   if (!file)
     return 0;
 
-  if ((fd = fopen (file, "r")) == 0)
+  if ((fd = fopen (file, "r")) == NULL)
     return 0;
 
   (void)fclose (fd);
@@ -1624,7 +1624,7 @@ io_export_data (enum export_type type, struct conf *conf)
       /* NOTREACHED */
     }
 
-  if (stream == 0)
+  if (stream == NULL)
     return;
 
   cb_export_header[type] (stream);
@@ -2774,7 +2774,7 @@ io_import_data (enum import_type type, struct conf *conf, char *stream_name)
                "Aborting..."));
 
   log = io_log_init ();
-  if (log == 0)
+  if (log == NULL)
     {
       if (stream != stdin)
         file_close (stream, __FILE_POS__);
@@ -2840,15 +2840,15 @@ io_log_init (void)
   struct io_file *log;
 
   logname = new_tempfile (logprefix, NOTESIZ);
-  RETVAL_IF (logname == 0, 0,
+  RETVAL_IF (logname == NULL, 0,
              _("Warning: could not create temporary log file, Aborting..."));
   log = mem_malloc (sizeof (struct io_file));
-  RETVAL_IF (log == 0, 0,
+  RETVAL_IF (log == NULL, 0,
              _("Warning: could not open temporary log file, Aborting..."));
   (void)snprintf (log->name, sizeof (log->name), "%s%s", logprefix, logname);
   mem_free (logname);
   log->fd = fopen (log->name, "w");
-  if (log->fd == 0)
+  if (log->fd == NULL)
     {
       ERROR_MSG (_("Warning: could not open temporary log file, Aborting..."));
       mem_free (log);
@@ -2871,7 +2871,7 @@ io_log_display (struct io_file *log, char *msg, char *pager)
   char *choices = "[y/n] ";
   int ans;
 
-  RETURN_IF (log == 0, _("No log file to display!"));
+  RETURN_IF (log == NULL, _("No log file to display!"));
   if (ui_mode == UI_CMDLINE)
     {
       printf ("\n%s %s", msg, choices);
@@ -3030,7 +3030,7 @@ io_get_pid (char *file)
   if (!file)
     return 0;
 
-  if ((fp = fopen (file, "r")) == 0)
+  if ((fp = fopen (file, "r")) == NULL)
     return 0;
 
   if (fscanf (fp, "%u", &pid) != 1)
diff --git a/src/keys.c b/src/keys.c
index 792a8ad..916d4e8 100644
--- a/src/keys.c
+++ b/src/keys.c
@@ -145,7 +145,7 @@ keys_free (void)
 
   for (key = 0; key < NBKEYS; key++)
     {
-      if (keys[key] == 0)
+      if (keys[key] == NULL)
         continue;
 
       i = &keys[key];
@@ -607,7 +607,7 @@ keys_check_missing_bindings (void)
 
   for (i = 0; i < NBKEYS; i++)
     {
-      if (keys[i] == 0)
+      if (keys[i] == NULL)
         return 1;
     }
   return 0;
@@ -620,7 +620,7 @@ keys_fill_missing (void)
 
   for (i = 0; i < NBKEYS; i++)
     {
-      if (keys[i] == 0)
+      if (keys[i] == NULL)
         {
           char *p, tmpbuf[BUFSIZ];
 
diff --git a/src/mem.c b/src/mem.c
index f719f36..ac43103 100644
--- a/src/mem.c
+++ b/src/mem.c
@@ -74,7 +74,7 @@ stats_add_blk (size_t size, const char *pos)
   struct mem_blk *o, **i;
 
   o = malloc (sizeof (*o));
-  EXIT_IF (o == 0, _("could not allocate memory to store block info"));
+  EXIT_IF (o == NULL, _("could not allocate memory to store block info"));
 
   mstats.ncall++;
 
@@ -120,7 +120,7 @@ xmalloc (size_t size)
 
   EXIT_IF (size == 0, _("xmalloc: zero size"));
   p = malloc (size);
-  EXIT_IF (p == 0, _("xmalloc: out of memory"));
+  EXIT_IF (p == NULL, _("xmalloc: out of memory"));
 
   return p;
 }
@@ -133,7 +133,7 @@ xcalloc (size_t nmemb, size_t size)
   EXIT_IF (nmemb == 0 || size == 0, _("xcalloc: zero size"));
   EXIT_IF (SIZE_MAX / nmemb < size, _("xcalloc: overflow"));
   p = calloc (nmemb, size);
-  EXIT_IF (p == 0, _("xcalloc: out of memory"));
+  EXIT_IF (p == NULL, _("xcalloc: out of memory"));
 
   return p;
 }
@@ -148,7 +148,7 @@ xrealloc (void *ptr, size_t nmemb, size_t size)
   EXIT_IF (new_size == 0, _("xrealloc: zero size"));
   EXIT_IF (SIZE_MAX / nmemb < size, _("xrealloc: overflow"));
   new_ptr = realloc (ptr, new_size);
-  EXIT_IF (new_ptr == 0, _("xrealloc: out of memory"));
+  EXIT_IF (new_ptr == NULL, _("xrealloc: out of memory"));
 
   return new_ptr;
 }
@@ -168,7 +168,7 @@ xstrdup (const char *str)
 void
 xfree (void *p)
 {
-  EXIT_IF (p == 0, _("xfree: null pointer"));
+  EXIT_IF (p == NULL, _("xfree: null pointer"));
   free (p);
 }
 
@@ -204,7 +204,7 @@ dbg_calloc (size_t nmemb, size_t size, const char *pos)
   EXIT_IF (nmemb > SIZE_MAX / size, _("overflow at %s"), pos);
 
   size *= nmemb;
-  if ((buf = dbg_malloc (size, pos)) == 0)
+  if ((buf = dbg_malloc (size, pos)) == NULL)
     return (void *)0;
 
   bzero (buf, size);
@@ -217,7 +217,7 @@ dbg_realloc (void *ptr, size_t nmemb, size_t size, const char *pos)
 {
   unsigned *buf, old_size, new_size, cpy_size;
 
-  if (ptr == 0)
+  if (ptr == NULL)
     return (void *)0;
 
   new_size = nmemb *size;
@@ -226,7 +226,7 @@ dbg_realloc (void *ptr, size_t nmemb, size_t size, const char *pos)
 
   EXIT_IF (nmemb > SIZE_MAX / size, _("overflow at %s"), pos);
 
-  if ((buf = dbg_malloc (new_size, pos)) == 0)
+  if ((buf = dbg_malloc (new_size, pos)) == NULL)
     return (void *)0;
 
   old_size = *((unsigned *)ptr - EXTRA_SPACE_START + BLK_SIZE);
@@ -244,11 +244,11 @@ dbg_strdup (const char *s, const char *pos)
   size_t size;
   char *buf;
 
-  if (s == 0)
+  if (s == NULL)
     return (char *)0;
 
   size = strlen (s);
-  if ((buf = dbg_malloc (size + 1, pos)) == 0)
+  if ((buf = dbg_malloc (size + 1, pos)) == NULL)
     return (char *)0;
 
   return strncpy (buf, s, size + 1);
@@ -259,7 +259,7 @@ dbg_free (void *ptr, const char *pos)
 {
   unsigned *buf, size;
 
-  EXIT_IF (ptr == 0, _("dbg_free: null pointer at %s"), pos);
+  EXIT_IF (ptr == NULL, _("dbg_free: null pointer at %s"), pos);
 
   buf = (unsigned *)ptr - EXTRA_SPACE_START;
   size = buf[BLK_SIZE];
@@ -286,7 +286,7 @@ dbg_free (void *ptr, const char *pos)
 static void
 dump_block_info (struct mem_blk *blk)
 {
-  if (blk == 0)
+  if (blk == NULL)
     return;
 
   printf (_("---==== MEMORY BLOCK ====----------------\n"));
diff --git a/src/recur.c b/src/recur.c
index a4932a1..2a08cd1 100644
--- a/src/recur.c
+++ b/src/recur.c
@@ -72,7 +72,7 @@ recur_add_exc (struct days **exc, long day)
   i = exc;
   for (;;)
     {
-      if (*i == 0 || (*i)->st > day)
+      if (*i == NULL || (*i)->st > day)
         {
           o->next = *i;
           *i = o;
@@ -243,7 +243,7 @@ recur_apoint_new (char *mesg, char *note, long start, long dur, char state,
   o = mem_malloc (sizeof (struct recur_apoint));
   o->rpt = mem_malloc (sizeof (struct rpt));
   o->mesg = mem_strdup (mesg);
-  o->note = (note != 0) ? mem_strdup (note) : 0;
+  o->note = (note != NULL) ? mem_strdup (note) : 0;
   o->start = start;
   o->state = state;
   o->dur = dur;
@@ -262,7 +262,7 @@ recur_apoint_new (char *mesg, char *note, long start, long dur, char state,
   i = &recur_alist_p->root;
   for (;;)
     {
-      if (*i == 0 || (*i)->start > start)
+      if (*i == NULL || (*i)->start > start)
         {
           o->next = *i;
           *i = o;
@@ -285,7 +285,7 @@ recur_event_new (char *mesg, char *note, long day, int id, int type, int freq,
   o = mem_malloc (sizeof (struct recur_event));
   o->rpt = mem_malloc (sizeof (struct rpt));
   o->mesg = mem_strdup (mesg);
-  o->note = (note != 0) ? mem_strdup (note) : 0;
+  o->note = (note != NULL) ? mem_strdup (note) : 0;
   o->day = day;
   o->id = id;
   o->rpt->type = type;
@@ -302,7 +302,7 @@ recur_event_new (char *mesg, char *note, long day, int id, int type, int freq,
   i = &recur_elist;
   for (;;)
     {
-      if (*i == 0 || (*i)->day > day)
+      if (*i == NULL || (*i)->day > day)
         {
           o->next = *i;
           *i = o;
@@ -510,7 +510,7 @@ recur_apoint_write (struct recur_apoint *o, FILE *f)
                      o->rpt->freq, recur_def2char (o->rpt->type),
                      lt->tm_mon + 1, lt->tm_mday, 1900 + lt->tm_year);
     }
-  if (o->exc != 0)
+  if (o->exc != NULL)
     recur_write_exc (o->exc, f);
   (void)fprintf (f, "} ");
   if (o->note != NULL)
@@ -554,7 +554,7 @@ recur_event_write (struct recur_event *o, FILE *f)
                      o->rpt->freq, recur_def2char (o->rpt->type),
                      end_mon, end_day, end_year);
     }
-  if (o->exc != 0)
+  if (o->exc != NULL)
     recur_write_exc (o->exc, f);
   (void)fprintf (f, "} ");
   if (o->note != NULL)
@@ -569,11 +569,11 @@ recur_save_data (FILE *f)
   struct recur_event *re;
   struct recur_apoint *ra;
 
-  for (re = recur_elist; re != 0; re = re->next)
+  for (re = recur_elist; re != NULL; re = re->next)
     recur_event_write (re, f);
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (ra = recur_alist_p->root; ra != 0; ra = ra->next)
+  for (ra = recur_alist_p->root; ra != NULL; ra = ra->next)
     recur_apoint_write (ra, f);
   pthread_mutex_unlock (&(recur_alist_p->mutex));
 }
@@ -665,7 +665,7 @@ recur_item_inday (long item_start, struct days *item_exc, int rpt_type,
   t = day_start;
   lt_day = *localtime (&t);
 
-  for (exc = item_exc; exc != 0; exc = exc->next)
+  for (exc = item_exc; exc != NULL; exc = exc->next)
     if (exc->st < day_end && exc->st >= day_start)
       return (0);
 
@@ -740,7 +740,7 @@ recur_event_erase (long start, unsigned num, unsigned delete_whole,
   struct recur_event *i, **iptr;
 
   iptr = &recur_elist;
-  for (i = recur_elist; i != 0; i = i->next)
+  for (i = recur_elist; i != NULL; i = i->next)
     {
       if (recur_item_inday (i->day, i->exc, i->rpt->type,
                             i->rpt->freq, i->rpt->until, start))
@@ -807,7 +807,7 @@ recur_apoint_erase (long start, unsigned num, unsigned delete_whole,
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
   iptr = &recur_alist_p->root;
-  for (i = recur_alist_p->root; i != 0; i = i->next)
+  for (i = recur_alist_p->root; i != NULL; i = i->next)
     {
       if (recur_item_inday (i->start, i->exc, i->rpt->type,
                             i->rpt->freq, i->rpt->until, start))
@@ -1061,7 +1061,7 @@ recur_apoint_check_next (struct notify_app *app, long start, long day)
   long real_recur_start_time;
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (i = recur_alist_p->root; i != 0; i = i->next)
+  for (i = recur_alist_p->root; i != NULL; i = i->next)
     {
       if (i->start > app->time)
         {
@@ -1095,7 +1095,7 @@ recur_get_apoint (long date, int num)
   int n = 0;
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (o = recur_alist_p->root; o != 0; o = o->next)
+  for (o = recur_alist_p->root; o != NULL; o = o->next)
     {
       if (recur_item_inday (o->start, o->exc, o->rpt->type,
                             o->rpt->freq, o->rpt->until, date))
@@ -1120,7 +1120,7 @@ recur_get_event (long date, int num)
   struct recur_event *o;
   int n = 0;
 
-  for (o = recur_elist; o != 0; o = o->next)
+  for (o = recur_elist; o != NULL; o = o->next)
     {
       if (recur_item_inday (o->day, o->exc, o->rpt->type,
                             o->rpt->freq, o->rpt->until, date))
@@ -1148,7 +1148,7 @@ recur_apoint_switch_notify (long date, int recur_nb)
   need_chk_notify = 0;
 
   pthread_mutex_lock (&(recur_alist_p->mutex));
-  for (o = recur_alist_p->root; o != 0; o = o->next)
+  for (o = recur_alist_p->root; o != NULL; o = o->next)
     {
       if (recur_item_inday (o->start, o->exc, o->rpt->type,
                             o->rpt->freq, o->rpt->until, date))
@@ -1187,7 +1187,7 @@ recur_event_paste_item (void)
     {
       struct days *exc;
 
-      for (exc = bkp_cut_recur_event.exc; exc != 0; exc = exc->next)
+      for (exc = bkp_cut_recur_event.exc; exc != NULL; exc = exc->next)
         exc->st += time_shift;
     }
 
@@ -1217,7 +1217,7 @@ recur_apoint_paste_item (void)
     {
       struct days *exc;
 
-      for (exc = bkp_cut_recur_apoint.exc; exc != 0; exc = exc->next)
+      for (exc = bkp_cut_recur_apoint.exc; exc != NULL; exc = exc->next)
         exc->st += time_shift;
     }
 
diff --git a/src/todo.c b/src/todo.c
index 8d7a4d5..4076510 100644
--- a/src/todo.c
+++ b/src/todo.c
@@ -182,7 +182,7 @@ todo_add (char *mesg, int id, char *note)
   absid = abs (id);
   for (;;)
     {
-      if (*i == 0 || abs ((*i)->id) > absid)
+      if (*i == NULL || abs ((*i)->id) > absid)
         {
           o->next = *i;
           *i = o;
@@ -201,7 +201,7 @@ todo_delete_note_bynum (unsigned num)
   struct todo *i;
 
   n = 0;
-  for (i = todolist; i != 0; i = i->next)
+  for (i = todolist; i != NULL; i = i->next)
     {
       if (n == num)
         {
@@ -225,7 +225,7 @@ todo_delete_bynum (unsigned num, enum eraseflg flag)
 
   n = 0;
   iptr = &todolist;
-  for (i = todolist; i != 0; i = i->next)
+  for (i = todolist; i != NULL; i = i->next)
     {
       if (n == num)
         {
@@ -451,7 +451,7 @@ todo_update_panel (int which_pan)
   /* Print todo item in the panel. */
   erase_window_part (win[TOD].p, 1, title_lines, win[TOD].w - 2,
                      win[TOD].h - 2);
-  for (i = todolist; i != 0; i = i->next)
+  for (i = todolist; i != NULL; i = i->next)
     {
       num_todo++;
       t_realpos = num_todo - first;
diff --git a/src/utils.c b/src/utils.c
index 8e4a447..d21debe 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -110,7 +110,7 @@ fatalbox (const char *errmsg)
   const int MSGLEN = WINCOL - 2;
   char msg[MSGLEN];
 
-  if (errmsg == 0)
+  if (errmsg == NULL)
     return;
 
   (void)strncpy (msg, errmsg, MSGLEN);
@@ -137,7 +137,7 @@ warnbox (const char *msg)
   const int MSGLEN = WINCOL - 2;
   char displmsg[MSGLEN];
 
-  if (msg == 0)
+  if (msg == NULL)
     return;
 
   (void)strncpy (displmsg, msg, MSGLEN);
@@ -405,7 +405,7 @@ updatestring (WINDOW *win, char **str, int x, int y)
     {
       len = strlen (buf);
       *str = mem_realloc (*str, len + 1, 1);
-      EXIT_IF (*str == 0, _("out of memory"));
+      EXIT_IF (*str == NULL, _("out of memory"));
       (void)memcpy (*str, buf, len + 1);
     }
 
diff --git a/src/wins.c b/src/wins.c
index ca5171f..a9e93e0 100644
--- a/src/wins.c
+++ b/src/wins.c
@@ -266,7 +266,7 @@ wins_init (void)
 void
 wins_scrollwin_init (struct scrollwin *sw)
 {
-  EXIT_IF (sw == 0, "null pointer");
+  EXIT_IF (sw == NULL, "null pointer");
   sw->win.p = newwin (sw->win.h, sw->win.w, sw->win.y, sw->win.x);
   sw->pad.p = newpad (sw->pad.h, sw->pad.w);
   sw->first_visible_line = 0;
@@ -277,7 +277,7 @@ wins_scrollwin_init (struct scrollwin *sw)
 void
 wins_scrollwin_delete (struct scrollwin *sw)
 {
-  EXIT_IF (sw == 0, "null pointer");
+  EXIT_IF (sw == NULL, "null pointer");
   delwin(sw->win.p);
   delwin(sw->pad.p);
 }