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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").