extern-inline: document fixes for ctype and wctype macros

[gnulib.git] / doc / posix-functions / isupper.texi

diff --git a/doc/posix-functions/isupper.texi b/doc/posix-functions/isupper.texi
index 8a7cfde..155ad12 100644 (file)
--- a/doc/posix-functions/isupper.texi
+++ b/doc/posix-functions/isupper.texi
@@ -2,14 +2,43 @@
 @section @code{isupper}
 @findex isupper
 
-POSIX specification: @url{http://www.opengroup.org/susv3xsh/isupper.html}
+POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/isupper.html}
 
 Gnulib module: ---
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function cannot be called from plain inline or extern inline functions
+on some platforms:
+OS X 10.8.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
 @end itemize
+
+Note: This function's behaviour depends on the locale, but does not support
+the multibyte characters that occur in strings in locales with
+@code{MB_CUR_MAX > 1} (this includes all the common UTF-8 locales).
+There are four alternative APIs:
+
+@table @code
+@item c_isupper
+This function operates in a locale independent way and returns true only for
+ASCII characters.  It is provided by the Gnulib module @samp{c-ctype}.
+
+@item iswupper
+This function operates in a locale dependent way, on wide characters.  In
+order to use it, you first have to convert from multibyte to wide characters,
+using the @code{mbrtowc} function.  It is provided by the Gnulib module
+@samp{wctype}.
+
+@item mb_isupper
+This function operates in a locale dependent way, on multibyte characters.
+It is provided by the Gnulib module @samp{mbchar}.
+
+@item uc_is_upper
+This function operates in a locale independent way, on Unicode characters.
+It is provided by the Gnulib module @samp{unictype/ctype-upper}.
+@end table