2.9BSD/usr/man/cat3/ctype.3

CTYPE(3)            UNIX Programmer's Manual             CTYPE(3)

NAME
     isalpha, isupper, islower, isdigit, isalnum, isspace,
     ispunct, isprint, iscntrl, isascii - character classifica-
     tion

SYNOPSIS
     #include <ctype.h>

     isalpha(c)

     . . .

DESCRIPTION
     These macros classify ASCII-coded integer values by table
     lookup.  Each is a predicate returning nonzero for true,
     zero for false.  _I_s_a_s_c_i_i is defined on all integer values;
     the rest are defined only where _i_s_a_s_c_i_i is true and on the
     single non-ASCII value EOF (see _s_t_d_i_o(3)).

     _i_s_a_l_p_h_a        _c is a letter

     _i_s_u_p_p_e_r        _c is an upper case letter

     _i_s_l_o_w_e_r        _c is a lower case letter

     _i_s_d_i_g_i_t        _c is a digit

     _i_s_a_l_n_u_m        _c is an alphanumeric character

     _i_s_s_p_a_c_e        _c is a space, tab, carriage return, newline,
                    or formfeed

     _i_s_p_u_n_c_t        _c is a punctuation character (neither control
                    nor alphanumeric)

     _i_s_p_r_i_n_t        _c is a printing character, code 040(8)
                    (space) through 0176 (tilde)

     _i_s_c_n_t_r_l        _c is a delete character (0177) or ordinary
                    control character (less than 040).

     _i_s_a_s_c_i_i        _c is an ASCII character, code less than 0200

SEE ALSO
     ascii(7)

Printed 8/3/83                                                  1