Convert all mutt_atoX functions to behave strictly.

* Remove the automatic conversion of NULL and '\0' to 0.  Add a flag
  for the cases that require lax evaluation.

* Make trailing characters generate an error by default for the
  mutt_atouX functions.  Add a flag for that case.  Most of the IMAP
  code parses numbers out of a stream, so add the flag to those
  calls.

* The mutt_atouX functions were also behaving incorrectly with
  invalid input, e.g. "ABC", returning and setting 0.  Fix them to
  return an error in those cases.

* Add a mutt_atoll() function, to be used in the next commit.

* Change converters to store 0 on error.  atos, atoi, and atoui were
  already doing this, but the others were not.

19 files changed, 180 insertions, 115 deletions

diff --git a/curs_main.c b/curs_main.c
index 8ab9173a..1b7f121c 100644
--- a/curs_main.c
+++ b/curs_main.c
@@ -931,7 +931,7 @@ int mutt_index_menu (void)
 	  break;
         }
 
-	if (mutt_atoi (buf, &i) < 0)
+	if (mutt_atoi (buf, &i, 0) < 0)
 	{
 	  mutt_error _("Argument must be a message number.");
 	  break;
diff --git a/edit.c b/edit.c
index 8bb8b636..33d33e27 100644
--- a/edit.c
+++ b/edit.c
@@ -156,7 +156,7 @@ be_include_messages (char *msg, char **buf, int *bufmax, int *buflen,
 
   while ((msg = strtok (msg, " ,")) != NULL)
   {
-    if (mutt_atoi (msg, &n) == 0 && n > 0 && n <= Context->msgcount)
+    if (mutt_atoi (msg, &n, 0) == 0 && n > 0 && n <= Context->msgcount)
     {
       n--;
 
diff --git a/gnupgparse.c b/gnupgparse.c
index 7142288e..9df7d502 100644
--- a/gnupgparse.c
+++ b/gnupgparse.c
@@ -217,7 +217,7 @@ static pgp_key_t parse_pub_line (char *buf, int *is_subkey, pgp_key_t k)
 	dprint (2, (debugfile, "key len: %s\n", p));
 
 	if (!(*is_subkey && option (OPTPGPIGNORESUB)) &&
-	    mutt_atos (p, &tmp.keylen) < 0)
+	    mutt_atos (p, &tmp.keylen, MUTT_ATOI_ALLOW_EMPTY) < 0)
 	  goto bail;
 	break;
       }
@@ -228,7 +228,7 @@ static pgp_key_t parse_pub_line (char *buf, int *is_subkey, pgp_key_t k)
 	if (!(*is_subkey && option (OPTPGPIGNORESUB)))
 	{
 	  int x = 0;
-	  if (mutt_atoi (p, &x) < 0)
+	  if (mutt_atoi (p, &x, MUTT_ATOI_ALLOW_EMPTY) < 0)
 	    goto bail;
 	  tmp.numalg = x;
 	  tmp.algorithm = pgp_pkalgbytype (x);
@@ -259,19 +259,19 @@ static pgp_key_t parse_pub_line (char *buf, int *is_subkey, pgp_key_t k)
           strncpy (tstr, p, 11);
           tstr[4] = '\0';
           tstr[7] = '\0';
-          if (mutt_atoi (tstr, &time.tm_year) < 0)
+          if (mutt_atoi (tstr, &time.tm_year, 0) < 0)
           {
             p = tstr;
             goto bail;
           }
           time.tm_year -= 1900;
-          if (mutt_atoi (tstr+5, &time.tm_mon) < 0)
+          if (mutt_atoi (tstr+5, &time.tm_mon, 0) < 0)
           {
             p = tstr+5;
             goto bail;
           }
           time.tm_mon -= 1;
-          if (mutt_atoi (tstr+8, &time.tm_mday) < 0)
+          if (mutt_atoi (tstr+8, &time.tm_mday, 0) < 0)
           {
             p = tstr+8;
             goto bail;
@@ -282,7 +282,7 @@ static pgp_key_t parse_pub_line (char *buf, int *is_subkey, pgp_key_t k)
         {
           unsigned long long secs;
 
-          if (mutt_atoull (p, &secs) < 0)
+          if (mutt_atoull (p, &secs, MUTT_ATOI_ALLOW_EMPTY) < 0)
             goto bail;
           tmp.gen_time = (time_t)secs;
         }
diff --git a/imap/command.c b/imap/command.c
index d9450852..340d5bb9 100644
--- a/imap/command.c
+++ b/imap/command.c
@@ -534,7 +534,8 @@ static int cmd_handle_untagged (IMAP_DATA* idata)
       dprint (2, (debugfile, "Handling EXISTS\n"));
 
       /* new mail arrived */
-      mutt_atoui (pn, &count);
+      if (mutt_atoui (pn, &count, MUTT_ATOI_ALLOW_TRAILING) < 0)
+        return 0;
 
       if (count < idata->max_msn)
       {
@@ -651,7 +652,7 @@ static void cmd_parse_expunge (IMAP_DATA* idata, const char* s)
 
   dprint (2, (debugfile, "Handling EXPUNGE\n"));
 
-  if (mutt_atoui (s, &exp_msn) < 0 ||
+  if (mutt_atoui (s, &exp_msn, MUTT_ATOI_ALLOW_TRAILING) < 0 ||
       exp_msn < 1 || exp_msn > idata->max_msn)
     return;
 
@@ -784,7 +785,7 @@ static void cmd_parse_fetch (IMAP_DATA* idata, char* s)
 
   dprint (3, (debugfile, "Handling FETCH\n"));
 
-  if (mutt_atoui (s, &msn) < 0)
+  if (mutt_atoui (s, &msn, MUTT_ATOI_ALLOW_TRAILING) < 0)
   {
     dprint (3, (debugfile, "cmd_parse_fetch: Skipping FETCH response - illegal MSN\n"));
     return;
@@ -853,7 +854,7 @@ static void cmd_parse_fetch (IMAP_DATA* idata, char* s)
     {
       s += 3;
       SKIPWS (s);
-      if (mutt_atoui (s, &uid) < 0)
+      if (mutt_atoui (s, &uid, MUTT_ATOI_ALLOW_TRAILING) < 0)
       {
         dprint (1, (debugfile, "cmd_parse_fetch: Illegal UID.  Skipping update.\n"));
         return;
@@ -1116,7 +1117,7 @@ static void cmd_parse_search (IMAP_DATA* idata, const char* s)
 
   while ((s = imap_next_word ((char*)s)) && *s != '\0')
   {
-    if (mutt_atoui (s, &uid) < 0)
+    if (mutt_atoui (s, &uid, MUTT_ATOI_ALLOW_TRAILING) < 0)
       continue;
     h = (HEADER *)int_hash_find (idata->uid_hash, uid);
     if (h)
diff --git a/imap/imap.c b/imap/imap.c
index 2376abb7..9147f1ee 100644
--- a/imap/imap.c
+++ b/imap/imap.c
@@ -900,7 +900,7 @@ static int imap_open_mailbox (CONTEXT* ctx)
       dprint (3, (debugfile, "Getting mailbox UIDVALIDITY\n"));
       pc += 3;
       pc = imap_next_word (pc);
-      if (mutt_atoui (pc, &idata->uid_validity) < 0)
+      if (mutt_atoui (pc, &idata->uid_validity, MUTT_ATOI_ALLOW_TRAILING) < 0)
         goto fail;
       status->uidvalidity = idata->uid_validity;
     }
@@ -909,7 +909,7 @@ static int imap_open_mailbox (CONTEXT* ctx)
       dprint (3, (debugfile, "Getting mailbox UIDNEXT\n"));
       pc += 3;
       pc = imap_next_word (pc);
-      if (mutt_atoui (pc, &idata->uidnext) < 0)
+      if (mutt_atoui (pc, &idata->uidnext, MUTT_ATOI_ALLOW_TRAILING) < 0)
         goto fail;
       status->uidnext = idata->uidnext;
     }
@@ -918,7 +918,7 @@ static int imap_open_mailbox (CONTEXT* ctx)
       dprint (3, (debugfile, "Getting mailbox HIGHESTMODSEQ\n"));
       pc += 3;
       pc = imap_next_word (pc);
-      if (mutt_atoull (pc, &idata->modseq) < 0)
+      if (mutt_atoull (pc, &idata->modseq, MUTT_ATOI_ALLOW_TRAILING) < 0)
         goto fail;
       status->modseq = idata->modseq;
     }
diff --git a/imap/message.c b/imap/message.c
index 48853b4f..4c859921 100644
--- a/imap/message.c
+++ b/imap/message.c
@@ -682,7 +682,7 @@ static int read_headers_condstore_qresync_updates (IMAP_DATA *idata,
 
     fetch_buf = imap_next_word (fetch_buf);
     if (!isdigit ((unsigned char) *fetch_buf) ||
-        mutt_atoui (fetch_buf, &header_msn) < 0)
+        mutt_atoui (fetch_buf, &header_msn, MUTT_ATOI_ALLOW_TRAILING) < 0)
       continue;
 
     if (header_msn < 1 || header_msn > msn_end ||
@@ -1139,7 +1139,7 @@ int imap_fetch_message (CONTEXT *ctx, MESSAGE *msg, int msgno, int headers)
 	if (ascii_strncasecmp ("UID", pc, 3) == 0)
 	{
 	  pc = imap_next_word (pc);
-	  if (mutt_atoui (pc, &uid) < 0)
+	  if (mutt_atoui (pc, &uid, MUTT_ATOI_ALLOW_TRAILING) < 0)
             goto bail;
 	  if (uid != HEADER_DATA(h)->uid)
 	    mutt_error (_("The message index is incorrect. Try reopening the mailbox."));
@@ -1825,7 +1825,7 @@ static int msg_fetch_header (CONTEXT* ctx, IMAP_HEADER* h, char* buf, FILE* fp)
 
   /* skip to message number */
   buf = imap_next_word (buf);
-  if (mutt_atoui (buf, &h->data->msn) < 0)
+  if (mutt_atoui (buf, &h->data->msn, MUTT_ATOI_ALLOW_TRAILING) < 0)
     return rc;
 
   /* find FETCH tag */
@@ -1899,7 +1899,7 @@ static int msg_parse_fetch (IMAP_HEADER *h, char *s)
     {
       s += 3;
       SKIPWS (s);
-      if (mutt_atoui (s, &h->data->uid) < 0)
+      if (mutt_atoui (s, &h->data->uid, MUTT_ATOI_ALLOW_TRAILING) < 0)
         return -1;
 
       s = imap_next_word (s);
@@ -1939,7 +1939,7 @@ static int msg_parse_fetch (IMAP_HEADER *h, char *s)
         dlen--;
       }
       *ptmp = 0;
-      if (mutt_atol (tmp, &h->content_length) < 0)
+      if (mutt_atol (tmp, &h->content_length, 0) < 0)
         return -1;
     }
     else if (!ascii_strncasecmp ("BODY", s, 4) ||
diff --git a/imap/util.c b/imap/util.c
index c529fd8f..6400dd68 100644
--- a/imap/util.c
+++ b/imap/util.c
@@ -597,7 +597,7 @@ int imap_get_literal_count(const char *buf, unsigned int *bytes)
   while (isdigit ((unsigned char) *pc))
     pc++;
   *pc = 0;
-  if (mutt_atoui (pn, bytes) < 0)
+  if (mutt_atoui (pn, bytes, 0) < 0)
     return -1;
 
   return 0;
@@ -1048,11 +1048,11 @@ int mutt_seqset_iterator_next (SEQSET_ITERATOR *iter, unsigned int *next)
     if (range_sep)
       *range_sep++ = '\0';
 
-    if (mutt_atoui (iter->substr_cur, &iter->range_cur))
+    if (mutt_atoui (iter->substr_cur, &iter->range_cur, 0))
       return -1;
     if (range_sep)
     {
-      if (mutt_atoui (range_sep, &iter->range_end))
+      if (mutt_atoui (range_sep, &iter->range_end, 0))
         return -1;
     }
     else
diff --git a/init.c b/init.c
index 151a0614..63cbdbda 100644
--- a/init.c
+++ b/init.c
@@ -2607,9 +2607,8 @@ static int parse_set (BUFFER *tmp, BUFFER *s, union pointer_long_t udata, BUFFER
       s->dptr++;
 
       mutt_extract_token (tmp, s, 0);
-      rc = mutt_atos (tmp->data, (short *) &val);
-
-      if (rc < 0 || !*tmp->data)
+      rc = mutt_atos (tmp->data, (short *) &val, 0);
+      if (rc < 0)
       {
 	snprintf (err->data, err->dsize, _("%s: invalid value (%s)"), tmp->data,
 		  rc == -1 ? _("format error") : _("number overflow"));
@@ -2671,9 +2670,8 @@ static int parse_set (BUFFER *tmp, BUFFER *s, union pointer_long_t udata, BUFFER
       s->dptr++;
 
       mutt_extract_token (tmp, s, 0);
-      rc = mutt_atol (tmp->data, (long *) &val);
-
-      if (rc < 0 || !*tmp->data)
+      rc = mutt_atol (tmp->data, (long *) &val, 0);
+      if (rc < 0)
       {
 	snprintf (err->data, err->dsize, _("%s: invalid value (%s)"), tmp->data,
 		  rc == -1 ? _("format error") : _("number overflow"));
diff --git a/lib.c b/lib.c
index 3c38f12b..f77707a7 100644
--- a/lib.c
+++ b/lib.c
@@ -829,7 +829,28 @@ void mutt_debug_f (const char *file, const int line, const char *function, const
 
 #endif /* DEBUG */
 
-int mutt_atos (const char *str, short *dst)
+
+/**********************************************************************
+ * mutt_atoX functions
+ *
+ * By default these all operate in a "strict mode", returning:
+ *
+ * * -1 if input is NULL or "".
+ *   Pass flag MUTT_ATOI_ALLOW_EMPTY to return 0 in that case.
+ *
+ * * -1 if there is trailing input after the number.
+ *   Pass flag MUTT_ATOI_ALLOW_TRAILING to return 0 in that case.
+ *
+ * * -2 if the number is out of range
+ *
+ * Note that the dst parameter will be set to 0 on error.
+ *********************************************************************/
+
+/* returns: 0 - successful conversion
+ *         -1 - error: invalid input
+ *         -2 - error: out of range
+ */
+int mutt_atos (const char *str, short *dst, int flags)
 {
   int rc;
   long res;
@@ -838,16 +859,20 @@ int mutt_atos (const char *str, short *dst)
 
   *t = 0;
 
-  if ((rc = mutt_atol (str, &res)) < 0)
+  if ((rc = mutt_atol (str, &res, flags)) < 0)
     return rc;
   if ((short) res != res)
     return -2;
 
   *t = (short) res;
-  return 0;
+  return rc;
 }
 
-int mutt_atoi (const char *str, int *dst)
+/* returns: 0 - successful conversion
+ *         -1 - error: invalid input
+ *         -2 - error: out of range
+ */
+int mutt_atoi (const char *str, int *dst, int flags)
 {
   int rc;
   long res;
@@ -856,48 +881,78 @@ int mutt_atoi (const char *str, int *dst)
 
   *t = 0;
 
-  if ((rc = mutt_atol (str, &res)) < 0)
+  if ((rc = mutt_atol (str, &res, flags)) < 0)
     return rc;
   if ((int) res != res)
     return -2;
 
   *t = (int) res;
-  return 0;
+  return rc;
 }
 
-int mutt_atol (const char *str, long *dst)
+/* returns: 0 - successful conversion
+ *         -1 - error: invalid input
+ *         -2 - error: out of range
+ */
+int mutt_atol (const char *str, long *dst, int flags)
 {
-  long r;
-  long *res = dst ? dst : &r;
+  long tmp, res;
+  long *t = dst ? dst : &tmp;
   char *e = NULL;
 
-  /* no input: 0 */
+  *t = 0;
+
   if (!str || !*str)
-  {
-    *res = 0;
-    return 0;
-  }
+    return (flags & MUTT_ATOI_ALLOW_EMPTY) ? 0 : -1;
 
   errno = 0;
-  *res = strtol (str, &e, 10);
-  if (e && *e != '\0')
+  res = strtol (str, &e, 10);
+
+  if (errno == ERANGE)
+    return -2;
+  if (e == str)
     return -1;
+  if ((*e != '\0') && !(flags & MUTT_ATOI_ALLOW_TRAILING))
+    return -1;
+
+  *t = res;
+  return 0;
+}
+
+/* returns: 0 - successful conversion
+ *         -1 - error: invalid input
+ *         -2 - error: out of range
+ */
+int mutt_atoll (const char *str, long long *dst, int flags)
+{
+  long long tmp, res;
+  long long *t = dst ? dst : &tmp;
+  char *e = NULL;
+
+  *t = 0;
+
+  if (!str || !*str)
+    return (flags & MUTT_ATOI_ALLOW_EMPTY) ? 0 : -1;
+
+  errno = 0;
+  res = strtoll (str, &e, 10);
+
   if (errno == ERANGE)
     return -2;
+  if (e == str)
+    return -1;
+  if ((*e != '\0') && !(flags & MUTT_ATOI_ALLOW_TRAILING))
+    return -1;
+
+  *t = res;
   return 0;
 }
 
-/* NOTE: this function's return value breaks with the above three functions.
- * The imap code lexes uint values out of a stream of characters without
- * tokenization.  The above functions return -1 if there is input beyond
- * the number.
- *
- * returns: 1 - successful conversion, with trailing characters
- *          0 - successful conversion
- *         -1 - invalid input
- *         -2 - input out of range
+/* returns: 0 - successful conversion
+ *         -1 - error: invalid input
+ *         -2 - error: out of range
  */
-int mutt_atoui (const char *str, unsigned int *dst)
+int mutt_atoui (const char *str, unsigned int *dst, int flags)
 {
   int rc;
   unsigned long res;
@@ -906,7 +961,7 @@ int mutt_atoui (const char *str, unsigned int *dst)
 
   *t = 0;
 
-  if ((rc = mutt_atoul (str, &res)) < 0)
+  if ((rc = mutt_atoul (str, &res, flags)) < 0)
     return rc;
   if ((unsigned int) res != res)
     return -2;
@@ -915,58 +970,60 @@ int mutt_atoui (const char *str, unsigned int *dst)
   return rc;
 }
 
-/* NOTE: this function's return value is different from mutt_atol.
- *
- * returns: 1 - successful conversion, with trailing characters
- *          0 - successful conversion
- *         -1 - invalid input
+/* returns: 0 - successful conversion
+ *         -1 - error: invalid input
+ *         -2 - error: out of range
  */
-int mutt_atoul (const char *str, unsigned long *dst)
+int mutt_atoul (const char *str, unsigned long *dst, int flags)
 {
-  unsigned long r;
-  unsigned long *res = dst ? dst : &r;
+  unsigned long tmp, res;
+  unsigned long *t = dst ? dst : &tmp;
   char *e = NULL;
 
-  /* no input: 0 */
+  *t = 0;
+
   if (!str || !*str)
-  {
-    *res = 0;
-    return 0;
-  }
+    return (flags & MUTT_ATOI_ALLOW_EMPTY) ? 0 : -1;
 
   errno = 0;
-  *res = strtoul (str, &e, 10);
-  if (*res == ULONG_MAX && errno == ERANGE)
+  res = strtoul (str, &e, 10);
+
+  if (errno == ERANGE)
+    return -2;
+  if (e == str)
     return -1;
-  if (e && *e != '\0')
-    return 1;
+  if ((*e != '\0') && !(flags & MUTT_ATOI_ALLOW_TRAILING))
+    return -1;
+
+  *t = res;
   return 0;
 }
 
-/* NOTE: this function's return value is different from mutt_atol.
- *
- * returns: 1 - successful conversion, with trailing characters
- *          0 - successful conversion
- *         -1 - invalid input
+/* returns: 0 - successful conversion
+ *         -1 - error: invalid input
+ *         -2 - error: out of range
  */
-int mutt_atoull (const char *str, unsigned long long *dst)
+int mutt_atoull (const char *str, unsigned long long *dst, int flags)
 {
-  unsigned long long r;
-  unsigned long long *res = dst ? dst : &r;
+  unsigned long long tmp, res;
+  unsigned long long *t = dst ? dst : &tmp;
   char *e = NULL;
 
-  /* no input: 0 */
+  *t = 0;
+
   if (!str || !*str)
-  {
-    *res = 0;
-    return 0;
-  }
+    return (flags & MUTT_ATOI_ALLOW_EMPTY) ? 0 : -1;
 
   errno = 0;
-  *res = strtoull (str, &e, 10);
-  if (*res == ULLONG_MAX && errno == ERANGE)
+  res = strtoull (str, &e, 10);
+
+  if (errno == ERANGE)
+    return -2;
+  if (e == str)
+    return -1;
+  if ((*e != '\0') && !(flags & MUTT_ATOI_ALLOW_TRAILING))
     return -1;
-  if (e && *e != '\0')
-    return 1;
+
+  *t = res;
   return 0;
 }
diff --git a/lib.h b/lib.h
index 1e98692d..9ee281f6 100644
--- a/lib.h
+++ b/lib.h
@@ -184,18 +184,26 @@ char *safe_strcat (char *, size_t, const char *);
 char *safe_strncat (char *, size_t, const char *, size_t);
 char *safe_strdup (const char *);
 
+/* mutt_atoX() flags:
+ *
+ * Without the flag, the function will return -1, but the dst parameter
+ * will still be set to 0. */
+#define MUTT_ATOI_ALLOW_EMPTY     (1<<0)  /* allow NULL or "" */
+#define MUTT_ATOI_ALLOW_TRAILING  (1<<1)  /* allow values after the number */
+
 /* strtol() wrappers with range checking; they return
  * 	 0 success
  * 	-1 format error
- * 	-2 overflow (for int and short)
- * the int pointer may be NULL to test only without conversion
+ * 	-2 out of range
+ * the dst pointer may be NULL to test only without conversion
  */
-int mutt_atos (const char *, short *);
-int mutt_atoi (const char *, int *);
-int mutt_atol (const char *, long *);
-int mutt_atoui (const char *, unsigned int *);
-int mutt_atoul (const char *, unsigned long *);
-int mutt_atoull (const char *, unsigned long long *);
+int mutt_atos (const char *, short *, int);
+int mutt_atoi (const char *, int *, int);
+int mutt_atol (const char *, long *, int);
+int mutt_atoll (const char *, long long *, int);
+int mutt_atoui (const char *, unsigned int *, int);
+int mutt_atoul (const char *, unsigned long *, int);
+int mutt_atoull (const char *, unsigned long long *, int);
 
 const char *mutt_stristr (const char *, const char *);
 const char *mutt_basename (const char *);
diff --git a/main.c b/main.c
index d813e885..7729150f 100644
--- a/main.c
+++ b/main.c
@@ -743,7 +743,7 @@ int main (int argc, char **argv, char **environ)
 
         case 'd':
 #ifdef DEBUG
-          mutt_atoi (optarg, &debuglevel);
+          mutt_atoi (optarg, &debuglevel, 0);
           printf (_("Debugging at level %d.\n"), debuglevel);
 #else
           printf ("%s", _("DEBUG was not defined during compilation.  Ignored.\n"));
diff --git a/menu.c b/menu.c
index a7fff292..59c94a2c 100644
--- a/menu.c
+++ b/menu.c
@@ -464,7 +464,7 @@ void menu_jump (MUTTMENU *menu)
     buf[0] = 0;
     if (mutt_get_field (_("Jump to: "), buf, sizeof (buf), 0) == 0 && buf[0])
     {
-      if (mutt_atoi (buf, &n) == 0 && n > 0 && n < menu->max + 1)
+      if (mutt_atoi (buf, &n, 0) == 0 && n > 0 && n < menu->max + 1)
       {
 	n--;	/* msg numbers are 0-based */
 	menu->current = n;
diff --git a/mh.c b/mh.c
index 67e63824..1cea86ea 100644
--- a/mh.c
+++ b/mh.c
@@ -154,12 +154,12 @@ static int mh_read_token (char *t, int *first, int *last)
   if ((p = strchr (t, '-')))
   {
     *p++ = '\0';
-    if (mutt_atoi (t, first) < 0 || mutt_atoi (p, last) < 0)
+    if (mutt_atoi (t, first, 0) < 0 || mutt_atoi (p, last, 0) < 0)
       return -1;
   }
   else
   {
-    if (mutt_atoi (t, first) < 0)
+    if (mutt_atoi (t, first, 0) < 0)
       return -1;
     *last = *first;
   }
@@ -512,7 +512,7 @@ static void mh_update_sequences (CONTEXT * ctx)
     else
       p = ctx->hdrs[l]->path;
 
-    if (mutt_atoi (p, &i) < 0)
+    if (mutt_atoi (p, &i, 0) < 0)
       continue;
 
     if (!ctx->hdrs[l]->read)
@@ -644,7 +644,7 @@ static void mh_update_maildir (struct maildir *md, struct mh_sequences *mhs)
     else
       p = md->h->path;
 
-    if (mutt_atoi (p, &i) < 0)
+    if (mutt_atoi (p, &i, 0) < 0)
       continue;
     f = mhs_check (mhs, i);
 
diff --git a/parse.c b/parse.c
index 9bf01338..4ebaec57 100644
--- a/parse.c
+++ b/parse.c
@@ -753,7 +753,8 @@ static BODY *_parse_multipart (FILE *fp, const char *boundary, LOFF_T end_off,
 #ifdef SUN_ATTACHMENT
         if (mutt_get_parameter ("content-lines", new->parameter))
         {
-	  mutt_atoi (mutt_get_parameter ("content-lines", new->parameter), &lines);
+	  mutt_atoi (mutt_get_parameter ("content-lines", new->parameter),
+                     &lines, 0);
 	  for ( ; lines; lines-- )
             if (ftello (fp) >= end_off || fgets (buffer, LONG_STRING, fp) == NULL)
               break;
@@ -941,7 +942,7 @@ time_t mutt_parse_date (const char *s, HEADER *h)
     switch (count)
     {
       case 0: /* day of the month */
-	if (mutt_atoi (t, &tm.tm_mday) < 0 || tm.tm_mday < 0)
+	if (mutt_atoi (t, &tm.tm_mday, 0) < 0 || tm.tm_mday < 0)
 	  return (-1);
 	if (tm.tm_mday > 31)
 	  return (-1);
@@ -954,7 +955,7 @@ time_t mutt_parse_date (const char *s, HEADER *h)
 	break;
 
       case 2: /* year */
-	if (mutt_atoi (t, &tm.tm_year) < 0 || tm.tm_year < 0)
+	if (mutt_atoi (t, &tm.tm_year, 0) < 0 || tm.tm_year < 0)
 	  return (-1);
         if (tm.tm_year < 50)
 	  tm.tm_year += 100;
@@ -1347,7 +1348,7 @@ int mutt_parse_rfc822_line (ENVELOPE *e, HEADER *hdr, char *line, char *p, short
            * HACK - mutt has, for a very short time, produced negative
            * Lines header values.  Ignore them.
            */
-          if (mutt_atoi (p, &hdr->lines) < 0 || hdr->lines < 0)
+          if (mutt_atoi (p, &hdr->lines, 0) < 0 || hdr->lines < 0)
             hdr->lines = 0;
         }
 
diff --git a/resize.c b/resize.c
index 01d84e46..120f967d 100644
--- a/resize.c
+++ b/resize.c
@@ -59,12 +59,12 @@ void mutt_resize_screen (void)
   }
   if (SLtt_Screen_Rows <= 0)
   {
-    if ((cp = getenv ("LINES")) != NULL && mutt_atoi (cp, &SLtt_Screen_Rows) < 0)
+    if ((cp = getenv ("LINES")) != NULL && mutt_atoi (cp, &SLtt_Screen_Rows, 0) < 0)
       SLtt_Screen_Rows = 24;
   }
   if (SLtt_Screen_Cols <= 0)
   {
-    if ((cp = getenv ("COLUMNS")) != NULL && mutt_atoi (cp, &SLtt_Screen_Cols) < 0)
+    if ((cp = getenv ("COLUMNS")) != NULL && mutt_atoi (cp, &SLtt_Screen_Cols, 0) < 0)
       SLtt_Screen_Cols = 80;
   }
 #ifdef USE_SLANG_CURSES
diff --git a/rfc2231.c b/rfc2231.c
index 68d051ca..426532bf 100644
--- a/rfc2231.c
+++ b/rfc2231.c
@@ -150,7 +150,7 @@ void rfc2231_decode_parameters (PARAMETER **headp)
          thus an overflow should never occur in a valid message, thus
          the value INT_MAX in case of overflow does not really matter
          (the goal is just to avoid undefined behavior). */
-      if (mutt_atoi (s, &index))
+      if (mutt_atoi (s, &index, 0) < 0)
         index = INT_MAX;
 
       conttmp = rfc2231_new_parameter ();
diff --git a/score.c b/score.c
index 5774d764..79985c39 100644
--- a/score.c
+++ b/score.c
@@ -117,7 +117,7 @@ int mutt_parse_score (BUFFER *buf, BUFFER *s, union pointer_long_t udata, BUFFER
     ptr->exact = 1;
     pc++;
   }
-  if (mutt_atoi (pc, &ptr->val) < 0)
+  if (mutt_atoi (pc, &ptr->val, 0) < 0)
   {
     FREE (&pattern);
     strfcpy (err->data, _("Error: score: invalid number"), err->dsize);
diff --git a/smtp.c b/smtp.c
index 4ebd06f2..2ab45ec1 100644
--- a/smtp.c
+++ b/smtp.c
@@ -89,7 +89,7 @@ static int smtp_code (char *buf, size_t len, int *n)
   code[1] = buf[1];
   code[2] = buf[2];
   code[3] = 0;
-  if (mutt_atoi (code, n) < 0)
+  if (mutt_atoi (code, n, 0) < 0)
     return -1;
   return 0;
 }
diff --git a/url.c b/url.c
index 9c8bcb4c..0eeb6d0b 100644
--- a/url.c
+++ b/url.c
@@ -162,7 +162,7 @@ static int ciss_parse_userhost (ciss_url_t *ciss, char *src)
   {
     int t;
     *p++ = '\0';
-    if (mutt_atoi (p, &t) < 0 || t < 0 || t > 0xffff)
+    if (mutt_atoi (p, &t, MUTT_ATOI_ALLOW_EMPTY) < 0 || t < 0 || t > 0xffff)
       return -1;
     ciss->port = (unsigned short)t;
   }