X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=doc%2Fposix-functions%2Fiscntrl.texi;h=db6ead5d60704dcfcfd4b8f11a645e1c844317d5;hb=f40e1532834adc754cac576a07d43b9556f89a97;hp=e93e2764e9fb572f0b1e9efd763c8c9c9a677c76;hpb=2b6c08c775ae4e80b52aa41058ea5939f778b44b;p=gnulib.git

diff --git a/doc/posix-functions/iscntrl.texi b/doc/posix-functions/iscntrl.texi
index e93e2764e..db6ead5d6 100644
--- a/doc/posix-functions/iscntrl.texi
+++ b/doc/posix-functions/iscntrl.texi
@@ -2,7 +2,7 @@
 @section @code{iscntrl}
 @findex iscntrl
 
-POSIX specification: @url{http://www.opengroup.org/susv3xsh/iscntrl.html}
+POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/iscntrl.html}
 
 Gnulib module: ---
 
@@ -13,3 +13,28 @@ Portability problems fixed by Gnulib:
 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_iscntrl
+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 iswcntrl
+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_iscntrl
+This function operates in a locale dependent way, on multibyte characters.
+It is provided by the Gnulib module @samp{mbchar}.
+
+@item uc_is_cntrl
+This function operates in a locale independent way, on Unicode characters.
+It is provided by the Gnulib module @samp{unictype/ctype-cntrl}.
+@end table