* doc/posix-headers/wchar.texi: Mention which platforms don’t
use Unicode for wchar_t.
---
 ChangeLog                    |  4 ++++
 doc/posix-headers/wchar.texi | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 924dae9a69..0acd1c9162 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2026-05-05  Paul Eggert  <[email protected]>
 
+       wchar-h: doc wchar_t limitations
+       * doc/posix-headers/wchar.texi: Mention which platforms don’t
+       use Unicode for wchar_t.
+
        localeinfo: wbctowc comment
        * lib/localeinfo.h: Improve comment.
 
diff --git a/doc/posix-headers/wchar.texi b/doc/posix-headers/wchar.texi
index 1fc638b13a..fddebff1ca 100644
--- a/doc/posix-headers/wchar.texi
+++ b/doc/posix-headers/wchar.texi
@@ -24,6 +24,16 @@ wchar.h
 Portability problems not fixed by Gnulib:
 @itemize
 @item
+In multibyte locales, @code{wchar_t} values need not be Unicode code points:
+FreeBSD 15, NetBSD 10, AIX, Solaris.
+@item
+In single-byte locales, @code{wchar_t} values need not be Unicode code points:
+FreeBSD 15, NetBSD 10, OpenBSD 7, macOS 26, Solaris, mingw, MSVC.
+@item
+@code{wchar_t} is only 16 bits, and so can represent only a
+UTF-16 subset of Unicode when @code{wchar_t} values are Unicode code points:
+32-bit AIX, mingw, MSVC.
+@item
 This header file leads to link errors and endless recursions or endless loops
 on some platforms:
 glibc version 2.5 or older, together with gcc version 4.3 or newer and the
-- 
2.54.0


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