NAME
isalnum
, isalnum_l
— alphanumeric single-byte
character test
SYNOPSIS
#include
<ctype.h>
int
isalnum
(int
c);
int
isalnum_l
(int
c, locale_t
locale);
DESCRIPTION
The
isalnum
()
function tests for any character for which
isalpha(3) or
isdigit(3) is true, and
isalnum_l
()
tests for any character for which isalpha_l(3) or isdigit_l(3) is true.
In the C locale, the complete list of alphanumeric characters is A–Z, a–z, 0, and 1–9. OpenBSD always uses the C locale for these functions, ignoring the global locale, the thread-specific locale, and the locale argument.
RETURN VALUES
These functions return zero if the character tests false or non-zero if the character tests true.
ENVIRONMENT
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).
SEE ALSO
isalpha(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), iswalnum(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)
STANDARDS
The isalnum
() function conforms to
ANSI X3.159-1989 (“ANSI C89”),
and isalnum_l
() to IEEE Std
1003.1-2008 (“POSIX.1”).
HISTORY
The isalnum
() function first appeared in
Version 7 AT&T UNIX, and
isalnum_l
() has been available since
OpenBSD 6.2.
CAVEATS
The argument c must be
EOF
or representable as an unsigned
char; otherwise, the result is undefined.