How to get the architecture of the client

[Xia, Arandar]

Hello,
I am developing a vfs module of samba, and want to get what the client is running on in the vfs module.
I find that %a in the configuration file is a substitution for the architecture of the remote machine, and I want to pass it into the vfs module like:
vfs objects = myvfs:client
           client: name = %a
But what I get in the vfs module is "%a" not the architecture of the client.
What is wrong and how to get what I want in the vfs module?

// Zeyi