getting seg fault during a simple memcached_get() call

[Jun8]

I have just started to experiment with memcached. I googled around and
from the snippest I could find I came up with the following simple
test code:

#include <libmemcached/memcached.h>
#include <stdio.h>
#include <string.h>

int main( int argc, char* argv[] )
{
        const char *key = "my_key";
        const char *value = "important value";
        size_t* len = 0;
        char* ret_value;

        memcached_return rc;
        memcached_st *memc = memcached_create(NULL);    // structure used in
talking to memcached server

        if( !memc ) {
                fprintf(stderr, "ERROR creating memcached structure\n");
        }

        memcached_server_add( memc, "localhost", MEMCACHED_DEFAULT_PORT );

        printf("Adding value\n");
        rc = memcached_set( memc,
                                                key, strlen(key),
                                                value, strlen(value),
                                                (time_t)0,                      
        // time to live
                                                (uint32_t)0                     
// no flags
                                        );
        if ( rc != MEMCACHED_SUCCESS ) {
                fprintf(stderr, "ERROR setting value in memcached!\n");
        }
        printf("\tDone\n");

        printf("Reading the value: \n");
        ret_value = memcached_get( memc,
                                                                key, 
strlen(key),       // key to search for
                                                                len,            
                // will hold length of returned value
                                                                (uint32_t)0,    
        // no flags
                                                                &rc );
        if ( rc != MEMCACHED_SUCCESS ) {
                fprintf(stderr, "ERROR getting value in memcached!\n");
        }
        printf("%d\n", len);

        memcached_free(memc);

        return 0;
}

When I run this, I get
Adding value
        Done
Reading the value:
Segmentation fault

When I use gdb, I get the following message
Program received signal SIGSEGV, Segmentation fault.
0x00132d04 in memcached_fetch () from /usr/lib/libmemcached.so.2

I used memcat and saw that the key,value is actually written on the
servfer. It's just that I have a problem with reading it.

Any help would be much appreciated. Thanks.