ISALPHA(3) | Library Functions Manual | ISALPHA(3) |
isalpha
, isalpha_l
— alphabetic single-byte character test
#include
<ctype.h>
int
isalpha
(int
c);
int
isalpha_l
(int
c, locale_t
locale);
The
isalpha
()
and
isalpha_l
()
functions test whether c represents a letter.
In the C locale, the complete list of alphabetic characters is A–Z and a–z. OpenBSD always uses the C locale for these functions, ignoring the global locale, the thread-specific locale, and the locale argument.
These functions return zero if the character tests false or non-zero if the character tests true.
On systems supporting non-ASCII single-byte character encodings,
these functions may return non-zero for additional characters, and the
results of isalnum
() may depend on the
LC_CTYPE
locale(1), but they never return non-zero
for any character for which iscntrl(3),
isdigit(3),
ispunct(3), or
isspace(3) is true.
isalnum(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), iswalpha(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)
The isalpha
() function conforms to
ANSI X3.159-1989 (“ANSI C89”),
and isalpha_l
() to IEEE Std
1003.1-2008 (“POSIX.1”).
The isalpha
() function first appeared in
Version 7 AT&T UNIX, and
isalpha_l
() has been available since
OpenBSD 6.2.
The argument c must be
EOF
or representable as an unsigned
char
; otherwise, the result is undefined.
September 5, 2017 | OpenBSD-current |