New upstream version 0.9.9upstream/0.9.9

1 files changed, 12 insertions, 0 deletions

diff --git a/doc/unitypes.texi b/doc/unitypes.texi
index 696ba88..68ab92f 100644
--- a/doc/unitypes.texi
+++ b/doc/unitypes.texi
@@ -13,3 +13,15 @@ taken from @code{<stdint.h>}, on platforms where this include file is present.
 @deftp Type ucs4_t
 This type represents a single Unicode character, outside of an UTF-32 string.
 @end deftp
+
+The types @code{ucs4_t} and @code{uint32_t} happen to be identical.  They differ
+in use and intent, however:
+@itemize @bullet
+@item
+Use @code{uint32_t *} to designate an UTF-32 string.  Use @code{ucs4_t} to
+designate a single Unicode character, outside of an UTF-32 string.
+@item
+Conversions functions that take an UTF-32 string as input will usually perform
+a range-check on the @code{uint32_t} values.  Whereas functions that are
+declared to take @code{ucs4_t} arguments will not perform such a range-check.
+@end itemize