Temporarily changing number of spaces in indentation

[Vineet Naik]

Hello,

I usually use 4 spaces (indent-tabs-mode set to nil) to indent php code.

I have the following line in .emacs file which I guess sets this behaviour

(setq c-basic-offset 4)

I am now temporarily working on some code which uses 8 spaces instead of 4.

So I tried evaluating (setq c-basic-offset 8) in scratch buffer. I see
8 in the mini buffer but it still indents 4 spaces.

If I change this line in .emacs file, save it and restart emacs, then
it uses 8 spaces correctly.

What is the correct way to achieve this ?

Also is there a mode in emacs to smartly adapt to the indentation
style used in a buffer ?

Regards,
Vineet