+ 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 ) */
+int isalnum( int c ) _PDCLIB_nothrow;
+
+/* Returns isupper( c ) || islower( c ) in the "C" locale.
+ In any other locale, also returns true for a locale-specific set of
+ alphabetic characters which are neither control characters, digits,
+ punctation, or whitespace.
+*/
+int isalpha( int c ) _PDCLIB_nothrow;
+
+/* Returns true if the character isspace() and used for seperating words within
+ a line of text. In the "C" locale, only ' ' and '\t' are considered blanks.
+*/
+int isblank( int c ) _PDCLIB_nothrow;
+
+/* Returns true if the character is a control character. */
+int iscntrl( int c ) _PDCLIB_nothrow;
+
+/* Returns true if the character is a decimal digit. Locale-independent. */
+int isdigit( int c ) _PDCLIB_nothrow;
+
+/* Returns true for every printing character except space (' '). */
+int isgraph( int c ) _PDCLIB_nothrow;
+
+/* Returns true for lowercase letters in the "C" locale.
+ In any other locale, also returns true for a locale-specific set of
+ characters which are neither control characters, digits, punctation, or
+ space (' '). In a locale other than the "C" locale, a character might test
+ true for both islower() and isupper().
+*/
+int islower( int c ) _PDCLIB_nothrow;
+
+/* Returns true for every printing character including space (' '). */
+int isprint( int c ) _PDCLIB_nothrow;