ISCNTRL(P) POSIX Programmer's Manual ISCNTRL(P)
iscntrl - test for a control character
int iscntrl(int c);
The iscntrl() function shall test whether c is a character of class cntrl in the program's
current locale; see the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 7,
The c argument is a type int, the value of which the application shall ensure is a charac-
ter representable as an unsigned char or equal to the value of the macro EOF. If the argu-
ment has any other value, the behavior is undefined.
The iscntrl() function shall return non-zero if c is a control character; otherwise, it
shall return 0.
No errors are defined.
The following sections are informative.
To ensure applications portability, especially across natural languages, only this func-
tion and those listed in the SEE ALSO section should be used for character classification.
isalnum() , isalpha() , isdigit() , isgraph() , islower() , isprint() , ispunct() , iss-
pace() , isupper() , isxdigit() , setlocale() , the Base Definitions volume of
IEEE Std 1003.1-2001, Chapter 7, Locale, <ctype.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 ISCNTRL(P)