Re: distinguish .h files

[Oleksandr Gavenko]

On 21.10.2010 15:53, Oleksandr Gavenko wrote:
> On 21.10.2010 13:37, Tassilo Horn wrote:
> > Oleksandr Gavenko<gavenko@bifit.com.ua> writes:
> >
> > Hi Oleksandr,
> >
> > > > Please have a look at
> > > >
> > > > (info "(emacs) Choosing Modes")
> > > Third, Emacs tries to determine the major mode by looking at the
> > > text at the start of the buffer, based on the variable
> > > `magic-mode-alist'. By default, this variable is `nil' (an empty
> > > list), so Emacs skips this step; however, you can customize it in your
> > > init file
> > >
> > > How long start of the buffer? Which variable control this behavior?
> >
> > I don't know exactly,...
> >
> > --8<---------------cut here---------------start------------->8---
> > (defun c++-header-file-p ()
> > "Return non-nil, if in a C++ header."
> > (and (string-match "\\.h$"
> > (or (buffer-file-name)
> > (buffer-name)))
> > (save-excursion
> > (re-search-forward "\\_<class\\_>" nil t))))
> >
> > (add-to-list 'magic-mode-alist
> > '(c++-header-file-p . c++-mode))
> > --8<---------------cut here---------------end--------------->8---
> I use your code to get this value (add this after 'string-match'):
>
> (message "%s" (- (point-max) (point-min)))
>
> I get 4000.
I get doc buffer for 'magic-mode-alist', go to source where this var defined
and search for keyword 'limit':

(defvar magic-mode-regexp-match-limit 4000
  "Upper limit on `magic-mode-alist' regexp matches.
Also applies to `magic-fallback-mode-alist'.")