From d501db962eae2b831a2497adc85a94e98064e969 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Thu, 28 Apr 2022 10:51:01 -0700 Subject: [PATCH] Document \807 etc. in raw byte display * doc/emacs/display.texi (Display Custom): Mention potential confusion in raw byte display. --- doc/emacs/display.texi | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/doc/emacs/display.texi b/doc/emacs/display.texi index 2ac0dca622..7a6c7f391b 100644 --- a/doc/emacs/display.texi +++ b/doc/emacs/display.texi @@ -2097,3 +2097,14 @@ Display Custom byte with a decimal value of 128 is displayed as @code{\200}. To change display to the hexadecimal format of @code{\x80}, set the variable @code{display-raw-bytes-as-hex} to @code{t}. +Care may be needed when interpreting a raw byte when copying +text from a terminal containing an Emacs session, or when a terminal's +@code{escape-glyph} face looks like the default face. For example, by +default Emacs displays the four characters @samp{\}, @samp{2}, +@samp{0}, @samp{0} with the same characters it displays a byte with +decimal value 128. The problem can be worse with hex displays, where +the raw byte 128 followed by the character @samp{7} is displayed as +@code{\x807}, which Emacs Lisp reads as the single character U+0807 +SAMARITAN LETTER IT; this confusion does not occur with the +corresponding octal display @code{\2007} because octal escapes contain +at most three digits. -- 2.35.1