-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
-// Provides functions for determining the locale-dependent type of a character,
-// plus locale-aware uppercase / lowercase conversions. (See also locale.h.)
-// ----------------------------------------------------------------------------
-
-#ifndef __CTYPE_H
-#define __CTYPE_H __CTYPE_H
-
-// ----------------------------------------------------------------------------
-// FUNCTIONS
-
-// returns nonzero if c is alphanumeric in the locale.
+/* $Id$ */
+
+/* 7.4 Character handling <ctype.h>
+
+ This file is part of the Public Domain C Library (PDCLib).
+ Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#ifndef _PDCLIB_CTYPE_H
+#define _PDCLIB_CTYPE_H _PDCLIB_CTYPE_H
+#include <_PDCLIB_int.h>
+_PDCLIB_BEGIN_EXTERN_C
+
+/* Character classification functions */
+
+/* Note that there is a difference between "whitespace" (any printing, non-
+ graph character, like horizontal and vertical tab), and "blank" (the literal
+ ' ' space character).
+
+ There will be masking macros for each of these later on, but right now I
+ focus on the functions only.
+*/
+
+/* Returns isalpha( c ) || isdigit( c ) */