Index: memcached.c
===================================================================
--- memcached.c	(revision 606)
+++ memcached.c	(working copy)
@@ -1257,15 +1257,15 @@
  *
  * returns a response string to send back to the client.
  */
-char *do_add_delta(item *it, const int incr, unsigned int delta, char *buf) {
+char *do_add_delta(item *it, const int incr, const unsigned int delta, char *buf) {
     char *ptr;
-    unsigned int value;
+    uint32_t value;
     int res;
 
     ptr = ITEM_data(it);
     while ((*ptr != '\0') && (*ptr < '0' && *ptr > '9')) ptr++;    // BUG: can't be true
 
-    value = strtol(ptr, NULL, 10);
+    value = strtoul(ptr, NULL, 10);
 
     if(errno == ERANGE) {
         return "CLIENT_ERROR cannot increment or decrement non-numeric value";
Index: thread.c
===================================================================
--- thread.c	(revision 606)
+++ thread.c	(working copy)
@@ -462,7 +462,7 @@
 /*
  * Does arithmetic on a numeric item value.
  */
-char *mt_add_delta(item *item, int incr, unsigned int delta, char *buf) {
+char *mt_add_delta(item *item, int incr, const unsigned int delta, char *buf) {
     char *ret;
 
     pthread_mutex_lock(&cache_lock);
Index: t/incrdecr.t
===================================================================
--- t/incrdecr.t	(revision 606)
+++ t/incrdecr.t	(working copy)
@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 
 use strict;
-use Test::More tests => 13;
+use Test::More tests => 16;
 use FindBin qw($Bin);
 use lib "$Bin/lib";
 use MemcachedTest;
@@ -30,6 +30,15 @@
 print $sock "decr num 5\r\n";
 is(scalar <$sock>, "0\r\n", "- 5 = 0");
 
+print $sock "incr num ".(2**32-2)."\r\n";
+is(scalar <$sock>, (2**32-2)."\r\n", "+ ".(2**32-2)." = ".(2**32-2));
+
+print $sock "incr num 1\r\n";
+is(scalar <$sock>, (2**32-1)."\r\n", "+ 1 = ".(2**32-1));
+
+print $sock "incr num 1\r\n";
+is(scalar <$sock>, "0\r\n", "+ 1 = 0");
+
 print $sock "decr bogus 5\r\n";
 is(scalar <$sock>, "NOT_FOUND\r\n", "can't decr bogus key");
 
@@ -40,5 +49,3 @@
 is(scalar <$sock>, "STORED\r\n", "stored text");
 print $sock "incr text 1\r\n";
 is(scalar <$sock>, "1\r\n", "hi - 1 = 0");
-
-
Index: doc/protocol.txt
===================================================================
--- doc/protocol.txt	(revision 606)
+++ doc/protocol.txt	(working copy)
@@ -279,8 +279,8 @@
   after the increment/decrement operation was carried out.
 
 Note that underflow in the "decr" command is caught: if a client tries
-to decrease the value below 0, the new value will be 0. Overflow in
-the "incr" command is not checked.
+to decrease the value below 0, the new value will be 0. Overflow in the
+"incr" command will wrap around the 32 bit mark.
 
 Note also that decrementing a number such that it loses length isn't
 guaranteed to decrement its returned length.  The number MAY be