ISCNTRL(3) Library Functions Manual ISCNTRL(3)

iscntrl
control character test

Standard C Library (libc, -lc)

#include <ctype.h>

int
iscntrl(int c);

The iscntrl() function tests for any control character.

The iscntrl() function returns zero if the character tests false and returns non-zero if the character tests true.

ctype(3), isalnum(3), isalpha(3), isascii(3), isblank(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)

The iscntrl() function conforms to ANSI X3.159-1989 (“ANSI C89”).

The argument to iscntrl() must be EOF or representable as an unsigned char; otherwise, the behavior is undefined. See the CAVEATS section of ctype(3) for more details.
April 17, 2008 NetBSD 9.0