iscntrl.3p (3422B)
- '\" et
- .TH ISCNTRL "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH PROLOG
- This manual page is part of the POSIX Programmer's Manual.
- The Linux implementation of this interface may differ (consult
- the corresponding Linux manual page for details of Linux behavior),
- or the interface may not be implemented on Linux.
- .\"
- .SH NAME
- iscntrl,
- iscntrl_l
- \(em test for a control character
- .SH SYNOPSIS
- .LP
- .nf
- #include <ctype.h>
- .P
- int iscntrl(int \fIc\fP);
- int iscntrl_l(int \fIc\fP, locale_t \fIlocale\fP);
- .fi
- .SH DESCRIPTION
- For
- \fIiscntrl\fR():
- The functionality described on this reference page is aligned with the
- ISO\ C standard. Any conflict between the requirements described here and the
- ISO\ C standard is unintentional. This volume of POSIX.1\(hy2017 defers to the ISO\ C standard.
- .P
- The
- \fIiscntrl\fR()
- and
- \fIiscntrl_l\fR()
- functions shall test whether
- .IR c
- is a character of class
- .BR cntrl
- in the current locale,
- or in the locale represented by
- .IR locale ,
- respectively; see the Base Definitions volume of POSIX.1\(hy2017,
- .IR "Chapter 7" ", " "Locale".
- .P
- The
- .IR c
- argument is a type
- .BR int ,
- the value of which the application shall ensure is a character
- representable as an
- .BR "unsigned char"
- or equal to the value of the macro EOF. If the argument has any other
- value, the behavior is undefined.
- .P
- The behavior is undefined if the
- .IR locale
- argument to
- \fIiscntrl_l\fR()
- is the special locale object LC_GLOBAL_LOCALE or is not a valid locale
- object handle.
- .SH "RETURN VALUE"
- The
- \fIiscntrl\fR()
- and
- \fIiscntrl_l\fR()
- functions shall return non-zero if
- .IR c
- is a control character; otherwise, they shall return 0.
- .SH ERRORS
- No errors are defined.
- .LP
- .IR "The following sections are informative."
- .SH EXAMPLES
- None.
- .SH "APPLICATION USAGE"
- To ensure applications portability, especially across natural
- languages, only these functions and the functions in the reference pages
- listed in the SEE ALSO section should be used for character classification.
- .SH RATIONALE
- None.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .IR "\fIisalnum\fR\^(\|)",
- .IR "\fIisalpha\fR\^(\|)",
- .IR "\fIisblank\fR\^(\|)",
- .IR "\fIisdigit\fR\^(\|)",
- .IR "\fIisgraph\fR\^(\|)",
- .IR "\fIislower\fR\^(\|)",
- .IR "\fIisprint\fR\^(\|)",
- .IR "\fIispunct\fR\^(\|)",
- .IR "\fIisspace\fR\^(\|)",
- .IR "\fIisupper\fR\^(\|)",
- .IR "\fIisxdigit\fR\^(\|)",
- .IR "\fIsetlocale\fR\^(\|)",
- .IR "\fIuselocale\fR\^(\|)"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "Chapter 7" ", " "Locale",
- .IR "\fB<ctype.h>\fP",
- .IR "\fB<locale.h>\fP"
- .\"
- .SH COPYRIGHT
- Portions of this text are reprinted and reproduced in electronic form
- from IEEE Std 1003.1-2017, Standard for Information Technology
- -- Portable Operating System Interface (POSIX), The Open Group Base
- Specifications Issue 7, 2018 Edition,
- Copyright (C) 2018 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 original Standard can be obtained online at
- http://www.opengroup.org/unix/online.html .
- .PP
- Any typographical or formatting errors that appear
- in this page are most likely
- to have been introduced during the conversion of the source files to
- man page format. To report such errors, see
- https://www.kernel.org/doc/man-pages/reporting_bugs.html .