NAME
isalpha —
alphabetic character test
SYNOPSIS
#include
<ctype.h>
int
isalpha(int
c);
DESCRIPTION
The
isalpha()
function tests for any character for which
isupper(3) or
islower(3) is true and for which none of
iscntrl(3),
isdigit(3),
ispunct(3), or
isspace(3) is true. In the C locale,
isalpha() returns true only for the characters for
which isupper(3) or
islower(3) is true.
RETURN VALUES
The isalpha() function returns zero if the
character tests false or non-zero if the character tests true.
SEE ALSO
isalnum(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)
STANDARDS
The isalpha() function conforms to
ANSI X3.159-1989
(“ANSI C89”).
HISTORY
The isalpha() function first appeared in
Version 7 AT&T UNIX.
CAVEATS
The argument to isalpha() must be
EOF or representable as an unsigned
char; otherwise, the result is undefined.