Maybe my copy of emacs 26 is too old.
If the visited file doesn’t exist, return -1.
If the visited file is deleted by external program, then does it return -1?
On 13 Mar 2018, 1:25 PM +0800, Radon Rosborough <address@hidden>, wrote:
If the buffer is not visiting a file, this function returns -1.
In my copy of Emacs 26, it says
If the visited file doesn’t exist, return -1.
Which is exactly what it does. *scratch* and *Messages* do not visit
files, so they have no recorded modtime, hence 0. If you visit a new
file but don't save it, you get -1.