ttyname_r: Make it work on MacOS X 10.4 and Solaris 10.

[gnulib.git] / lib / c-ctype.h

diff --git a/lib/c-ctype.h b/lib/c-ctype.h
index 395c7a1..6404fd4 100644 (file)
--- a/lib/c-ctype.h
+++ b/lib/c-ctype.h
@@ -5,7 +5,7 @@
    <ctype.h> functions' behaviour depends on the current locale set via
    setlocale.
 
-   Copyright (C) 2000-2003, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2000-2003, 2006, 2008-2010 Free Software Foundation, Inc.
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -27,6 +27,11 @@ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 #include <stdbool.h>
 
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 /* The functions defined in this file assume the "C" locale and a character
    set without diacritics (ASCII-US or EBCDIC-US or something like that).
    Even if the "C" locale on a particular system is an extension of the ASCII
@@ -98,6 +103,21 @@ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 /* Function declarations. */
 
+/* Unlike the functions in <ctype.h>, which require an argument in the range
+   of the 'unsigned char' type, the functions here operate on values that are
+   in the 'unsigned char' range or in the 'char' range.  In other words,
+   when you have a 'char' value, you need to cast it before using it as
+   argument to a <ctype.h> function:
+
+         const char *s = ...;
+         if (isalpha ((unsigned char) *s)) ...
+
+   but you don't need to cast it for the functions defined in this file:
+
+         const char *s = ...;
+         if (c_isalpha (*s)) ...
+ */
+
 extern bool c_isascii (int c); /* not locale dependent */
 
 extern bool c_isalnum (int c);
@@ -267,4 +287,9 @@ extern int c_toupper (int c);
 
 #endif /* optimizing for speed */
 
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* C_CTYPE_H */