isalpha3
Alphabetic character test
Usage
#include <ctype.h>
int
isalpha(int c);
int
isalpha_l(int c, locale_t loc);
Library
Standard C Library (libc, -lc)
Overview
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.
Releases
87 releases since FreeBSD 2.0.5-RELEASE; the text changed 47 times.