Append/prepend commands. Introduce new storage commands "append" and "prepend" for atomic value modification. They follow generic storage commands interface as described in doc/protocol.txt: <command name> <key> <flags> <exptime> <bytes>\r\n <data block>\r\n Current implementation involves memcpy() twice to combine values on writing (i.e. full resulting value are copied), but truly atomic (and even threadsafe).

#!/usr/bin/perl

use strict;
use Test::More tests => 1;
use FindBin qw($Bin);
use lib "$Bin/lib";
use MemcachedTest;

my $server = new_memcached();
my $sock = $server->sock;

print $sock "boguscommand slkdsldkfjsd\r\n";
is(scalar <$sock>, "ERROR\r\n", "got error back");