isalnum



ISALNUM(3)                 Library Functions Manual                 ISALNUM(3)


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.

OpenBSD 6.4                    September 5, 2017                   OpenBSD 6.4

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