ISALPHA(3)             FreeBSD Library Functions Manual             ISALPHA(3)

NAME

     isalpha, isalpha_l - alphabetic character test

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <ctype.h>

     int
     isalpha(int c);

     int
     isalpha_l(int c, locale_t loc);

DESCRIPTION

     The isalpha() and isalpha_l() functions test for any character for which
     isupper(3), isupper_l(3) or islower(3), islower_l(3) is true.  The value
     of the argument must be representable as an unsigned char or the value of
     EOF.

     In the ASCII character set, this includes the following characters (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''

     The isalpha_l() function takes an explicit locale argument, whereas the
     isalpha() function uses the current global or per-thread locale.

RETURN VALUES

     The isalpha() and isalpha_l() functions return zero if the character
     tests false and return 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() or
     iswalpha_l() function should be used instead.

SEE ALSO

     ctype(3), ctype_l(3), islower(3), islower_l(3), isupper(3), isupper_l(3),
     iswalpha(3), iswalpha_l(3), xlocale(3), ascii(7)

STANDARDS

     The isalpha() function conforms to ISO/IEC 9899:1990 ("ISO C90").  The
     isalpha_l() function conforms to IEEE Std 1003.1-2008 ("POSIX.1").

FreeBSD 15.1-STABLE-HBSD       December 19, 2022                    ISALPHA(3)