g-wan kv store KV_INCR_KEY

Question

How to use the KV_INCR_KEY?
I found a useful feature in gwan api, but without any sample.
I want to add items to the KV store with this as primary key.
Also, how to get the value of this key?

Answer 1

The KV_INCR_KEY value is a flag intended to be passed to k_add().

You get the newly inserted key's value by checking the return value of k_add(). The documentation states:

kv_add(): add/update a value associated to a key
return: 0:out of memory, else:pointer on existing/inserted kv_item struct

This was derived from an idea discussed on the G-WAN forum. And, like for some other flags (timestamp or persistence, for example), it has not not been implemented yet (KV_NO_UPDATE is functional).

Since what follows the next version (focussed on new scripted languages) is a kind of zero-configuration mapReduce, the KV store will get more attention soon.