ISCNTRL(3)             FreeBSD Library Functions Manual             ISCNTRL(3)

NAME

     iscntrl, iscntrl_l - control character test

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <ctype.h>

     int
     iscntrl(int c);

     int
     iscntrl_l(int c, locale_t loc);

DESCRIPTION

     The iscntrl() and iscntrl_l() functions test for any control character.
     The value of the argument must be representable as an unsigned char or
     the value of EOF.

     In the ASCII character set, this includes the following characters (with
     their numeric values shown in octal):

     000 NUL       001 SOH       002 STX       003 ETX       004 EOT
     005 ENQ       006 ACK       007 BEL       010 BS        011 HT
     012 NL        013 VT        014 NP        015 CR        016 SO
     017 SI        020 DLE       021 DC1       022 DC2       023 DC3
     024 DC4       025 NAK       026 SYN       027 ETB       030 CAN
     031 EM        032 SUB       033 ESC       034 FS        035 GS
     036 RS        037 US        177 DEL

     The iscntrl_l() function takes an explicit locale argument, whereas the
     iscntrl() function uses the current global or per-thread locale.

RETURN VALUES

     The iscntrl() and iscntrl_l() functions return zero if the character
     tests false and return non-zero if the character tests true.

COMPATIBILITY

     The 4.4BSD extension of accepting arguments outside of the range of the
     unsigned char type in locales with large character sets is considered
     obsolete and may not be supported in future releases.  The iswcntrl() or
     iswcntrl_l() function should be used instead.

SEE ALSO

     ctype(3), ctype_l(3), iswcntrl(3), iswcntrl_l(3), xlocale(3), ascii(7)

STANDARDS

     The iscntrl() function conforms to ISO/IEC 9899:1990 ("ISO C90").  The
     iscntrl_l() function conforms to IEEE Std 1003.1-2008 ("POSIX.1").

HISTORY

     The iscntrl() function first appeared in Version 7 AT&T UNIX.

FreeBSD 15.1-STABLE-HBSD       December 19, 2022                    ISCNTRL(3)