How to know client (user) request cancel

[shivu prasad]

Hi,
I my module I will send the request challenge to get input from user via
client.
If user cancel the request, How to know it.
I try to check it via     *request->packet->code*
DEBUG("<----------------Request code = %d--------------------->",
request->packet->code);
But it returning 1 in both user press ok or cancel.

is in particular attribute tells the user cancel the request?

thanks,
Shivaprasad