From 73508e62459113be4c7c101648afbe541dd18558 Mon Sep 17 00:00:00 2001 From: Eli Zaretskii Date: Tue, 29 Jan 2019 18:28:13 +0200 Subject: [PATCH] Improve documentation of face numbers * doc/lispref/display.texi (Face Functions): Mention where the face number is used and that it depends on the 'face' property of the face symbol. Improve indexing. --- doc/lispref/display.texi | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi index b3ce7fbf6af..921d58a1f3a 100644 --- a/doc/lispref/display.texi +++ b/doc/lispref/display.texi @@ -3038,10 +3038,17 @@ value, which inherits from @var{face}'s global definition. This function returns a list of all defined face names. @end defun +@cindex face number +@cindex face property of face symbols @defun face-id face This function returns the @dfn{face number} of face @var{face}. This is a number that uniquely identifies a face at low levels within Emacs. It is seldom necessary to refer to a face by its face number. +However, functions that manipulate glyphs, such as +@code{make-glyph-code} and @code{glyph-face} (@pxref{Glyphs}) access +the face numbers internally. Note that the face number is stored as +the value of the @code{face} property of the face symbol, so we +recommend not to set that property of a face to any value of your own. @end defun @defun face-documentation face