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.