char *key= result->item_key;
result->key_length= 0;
- for (size_t prefix_length= memcached_array_size(instance->root->_namespace); !(iscntrl(*string_ptr) || isspace(*string_ptr)) ; string_ptr++)
+ for (ptrdiff_t prefix_length= memcached_array_size(instance->root->_namespace); !(iscntrl(*string_ptr) || isspace(*string_ptr)) ; string_ptr++)
{
if (prefix_length == 0)
{