The simplest way to examine text properties is to ask for the value of
a particular property of a particular character. For that, use
get-text-property. Use text-properties-at to get the
entire property list of a character. See section Property Search Functions, for
functions to examine the properties of a number of characters at once.
Under FSF Emacs, these functions handle both strings and buffers. (Keep in mind that positions in a string start from 0, whereas positions in a buffer start from 1.) Under XEmacs, these functions currently only handle buffers. This may change in the future.
If there is no prop property strictly speaking, but the character
has a category that is a symbol, then get-text-property returns
the prop property of that symbol.
nil, it defaults to the current buffer.
(setq default-text-properties '(foo 69))
;; Make sure character 1 has no properties of its own.
(set-text-properties 1 2 nil)
;; What we get, when we ask, is the default value.
(get-text-property 1 'foo)
=> 69