mapping tab key in vim

Question

I'm using Vim 7.4. I have mapped "Tab" key in normal mode to switch to insert mode.

nnoremap <tab> a

This works fine in .txt file but not in .cpp files. Why is that?

Besides mapping, I also have clang_complete settings in my .vimrc file.

Answer 1

:verbose nmap <Tab>

will show you the current mapping(s). If two are listed, the one with an @ prefix before the right-hand side is a buffer-local mapping that overrides your global one. You then need to find its definition (somewhere in ftplugin/cpp*.vim, or via an :autocmd FileType cpp) and disable it.

Answer 2

I put it using:

map <Tab> to

and it worked