Source code formatting uses a 4 column tab spacing, currently with tabs preserved (i.e. tabs are not expanded to spaces).
For emacs, add the following (or something similar) to your ~/.emacs initialization file:
;; check for files with a path containing "postgres" or "pgsql"
(setq auto-mode-alist (cons '("\\(postgres\\|pgsql\\).*\\.[ch]\\'" . pgsql-c-mode) auto-mode-alist))
(setq auto-mode-alist (cons '("\\(postgres\\|pgsql\\).*\\.cc\\'" . pgsql-c-mode) auto-mode-alist))
(defun pgsql-c-mode ()
;; sets up formatting for Postgres C code
(interactive)
(c-mode)
(setq-default tab-width 4)
(c-set-style "bsd") ; set c-basic-offset to 4, plus other stuff
(c-set-offset 'case-label '+) ; tweak case indent to match PG custom
(setq indent-tabs-mode t)) ; make sure we keep tabs when indenting
For vi, your ~/.vimrc or equivalent file should contain the following:
set tabstop=4
or equivalently from within vi, try :set ts=4
The text browsing tools more and less can be invoked as
more -x4
less -x4