SYNOPSIS

     #include <ctype.h>

     int
     isalpha(int c);

DESCRIPTION

     The isalpha() function tests for any character for which isupper(3) or
     islower(3) is true.  For single C chars locales (see multibyte(3)) the
     value of the argument is representable as an unsigned char or the value
     of EOF.  In the ASCII character set, this includes the following charac-
     ters (with their numeric values shown in octal):

     101 ``A''     102 ``B''     103 ``C''     104 ``D''     105 ``E''
     106 ``F''     107 ``G''     110 ``H''     111 ``I''     112 ``J''
     113 ``K''     114 ``L''     115 ``M''     116 ``N''     117 ``O''
     120 ``P''     121 ``Q''     122 ``R''     123 ``S''     124 ``T''
     125 ``U''     126 ``V''     127 ``W''     130 ``X''     131 ``Y''
     132 ``Z''     141 ``a''     142 ``b''     143 ``c''     144 ``d''
     145 ``e''     146 ``f''     147 ``g''     150 ``h''     151 ``i''
     152 ``j''     153 ``k''     154 ``l''     155 ``m''     156 ``n''
     157 ``o''     160 ``p''     161 ``q''     162 ``r''     163 ``s''
     164 ``t''     165 ``u''     166 ``v''     167 ``w''     170 ``x''
     171 ``y''     172 ``z''

RETURN VALUES

     The isalpha() function returns zero if the character tests false and
     returns non-zero if the character tests true.

COMPATIBILITY

     The 4.4BSD extension of accepting arguments outside of the range of the
     unsigned char type in locales with large character sets is considered
     obsolete and may not be supported in future releases.  The iswalpha()
     function should be used instead.

SEE ALSO

     ctype(3), islower(3), isupper(3), iswalpha(3), multibyte(3), ascii(7),
     isalnum_l

STANDARDS

     The isalpha() function conforms to ISO/IEC 9899:1990 (``ISO C90'').

BSD                             August 21, 2004                            BSD