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.