mark-whole-buffer

mark-whole-buffer is an interactive compiled Lisp function in `simple.el'.

It is bound to C-x h, <menu-bar> <edit> <mark-whole-buffer>.

(mark-whole-buffer)

This function is for interactive use only.

Put point at beginning and mark at end of buffer.
If narrowing is in effect, only uses the accessible part of the buffer.
You probably should not use this function in Lisp programs;
it is usually a mistake for a Lisp function to use any subroutine
that uses or sets the mark.