If non-nil, generate new buffers. The default is t. If this is a function, call that function with three parameters: The type, the to address and the group name. (Any of these may be nil.) The function should return the new buffer name.

This variable says how many old message buffers to keep. If there are more message buffers than this, the oldest buffer will be killed. The default is 10. If this variable is nil, no old message buffers will ever be killed.

After sending a message, the buffer is renamed from, for instance, `*reply to Lars*' to `*sent reply to Lars*'. If you don't like this, set this variable to a function that renames the buffer in a manner you like. If you don't want to rename the buffer at all, you can say:

(setq message-send-rename-function 'ignore)

If non-nil, kill the buffer immediately on exit.