26683: add some notes on LC_CTYPE

2 files changed, 17 insertions, 1 deletions

diff --git a/Doc/Zsh/params.yo b/Doc/Zsh/params.yo
index 3da63fa78..dec742f07 100644
--- a/Doc/Zsh/params.yo
+++ b/Doc/Zsh/params.yo
@@ -906,7 +906,12 @@ information within ranges in glob brackets and for sorting.
 vindex(LC_CTYPE)
 item(tt(LC_CTYPE) <S>)(
 This variable determines the locale category for character handling
-functions.
+functions.  If the tt(MULTIBYTE) option is in effect this variable or
+tt(LANG) should contain a value that reflects the character set in
+use, even if it is a single-byte character set, unless only the
+7-bit subset (ASCII) is used.  For example, if the character set
+is ISO-8859-1, a suitable value might be tt(en_US.iso88591) (certain
+Linux distributions) or tt(en_US.ISO8859-1) (MacOS).
 )
 vindex(LC_MESSAGES)
 item(tt(LC_MESSAGES) <S>)(
diff --git a/Doc/Zsh/roadmap.yo b/Doc/Zsh/roadmap.yo
index d9b5d53ce..fd87c74ab 100644
--- a/Doc/Zsh/roadmap.yo
+++ b/Doc/Zsh/roadmap.yo
@@ -50,6 +50,17 @@ by the shell, but the degree of support in terminal emulators is variable.
 There is some discussion of this in the shell FAQ,
 http://zsh.dotsrc.org/FAQ/ .  Note in particular that for combining
 characters to be handled the option tt(COMBINING_CHARS) needs to be set.
+Because the shell is now more sensitive to the definition of the
+character set, note that if you are upgrading from an older version of
+the shell you should ensure that the appropriate variable, either
+tt(LANG) (to affect all aspects of the shell's operation) or
+tt(LC_CTYPE) (to affect only the handling of character sets) is set to
+an appropriate value.  This is true even if you are using a
+single-byte character set including extensions of ASCII such as
+tt(ISO-8859-1) or tt(ISO-8859-15).  See the description of tt(LC_CTYPE)
+in
+ifnzman(noderef(Parameters))\
+ifzman(zmanref(zshparam)).
 
 subsect(Completion)