How do I make vim automatically apply c++ syntax highlight on Arduino files (.ino/.pde)?

How do I make vim automatically apply c++ syntax highlight on Arduino files (.ino/.pde)?

Or how does vim syntax highlight know what is a c++ file? And how can I tell him that files that is called .ino and .pde is also c++ files.

Add something like this to ~/.vimrc:

autocmd BufNewFile,BufReadPost *.ino,*.pde set filetype=cpp

Or more correctly, to ~/.vim/ftdetect/cpp.vim.

Vim searches for syntax files named {name}.vim where name represents the language, for example cpp.vim for c++ files. If you want that an .ino file has his own syntax highlight create a file called ~/.vim/syntax/ino.vim and you can start use it with :set syntax=ino. In your case you can create a link to a cpp.vim file.

ln -s /usr/share/vim/vimcurrent/syntax/cpp.vim ~/.vim/syntax/ino.vim

You can create an autocommand as follows:

au BufRead,BufNewFile *.pde,*.ino set filetype=c++

Put this into your .vimrc to make the setting persistent.