Hi Anand,
[ please reply to list or keep it as cc ]
Anand> Hi Paul, Thanks I found it working. I have one more question
Anand> GVIM, provides the auto completions with the exhaustive list of
Anand> all the possibilities. while typing in .c file (for example
Anand> GS_AM_ will give all the auto completions for all the tokens
Anand> strating with GS_AM.) In emacs also M-/ gives the completions
Anand> which are there in current buffer. Furhter it gives the case
Anand> insensitive one.(the cases are ignored). But it will not give the
Anand> completions from the TAGS file It does not consider other files
Anand> and buffers. Is there any way to do it in emacs.?
As usual with emacs, there isn't a single way but many, none of them
being "the one".
A lot of people wrote packages for completion, I think they should be
listed and detailled here :
http://www.emacswiki.org/emacs/CategoryCompletion
Some of them will come bundled to your emacs distribution, some others
won't. Please read and find out which suits the best your needs.