CATOPEN
Section: POSIX Programmer's Manual (3P)
Updated: 2017
Page Index
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.
NAME
catopen
--- open a message catalog
SYNOPSIS
#include <nl_types.h>
nl_catd catopen(const char *name, int oflag);
DESCRIPTION
The
catopen()
function shall open a message catalog and return a message catalog
descriptor. The
name
argument specifies the name of the message catalog to be opened. If
name
contains a
'/',
then
name
specifies a pathname for the message catalog. Otherwise, the
environment variable
NLSPATH
is used with
name
substituted for the
%N
conversion specification (see the Base Definitions volume of POSIX.1-2017,
Chapter 8,
Environment Variables);
if
NLSPATH
exists in the environment when the process starts, then if the process
has appropriate privileges, the behavior of
catopen()
is undefined. If
NLSPATH
does not exist in the environment, or if a message catalog cannot be
found in any of the components specified by
NLSPATH,
then an implementation-defined default path shall be used. This default
may be affected by the setting of
LC_MESSAGES
if the value of
oflag
is NL_CAT_LOCALE, or the
LANG
environment variable if
oflag
is 0.
A message catalog descriptor shall remain valid in a process until that
process closes it, or a successful call to one of the
exec
functions. A change in the setting of the
LC_MESSAGES
category may invalidate existing open catalogs.
If a file descriptor is used to implement message catalog descriptors,
the FD_CLOEXEC flag shall be set; see
<fcntl.h>.
If the value of the
oflag
argument is 0, the
LANG
environment variable is used to locate the catalog without regard to
the
LC_MESSAGES
category. If the
oflag
argument is NL_CAT_LOCALE, the
LC_MESSAGES
category is used to locate the message catalog (see the Base Definitions volume of POSIX.1-2017,
Section 8.2, Internationalization Variables).
RETURN VALUE
Upon successful completion,
catopen()
shall return a message catalog descriptor for use on subsequent calls to
catgets()
and
catclose().
Otherwise,
catopen()
shall return (
nl_catd)
-1 and set
errno
to indicate the error.
ERRORS
The
catopen()
function may fail if:
- EACCES
-
Search permission is denied for the component of the path prefix of the
message catalog or read permission is denied for the message catalog.
- EMFILE
-
All file descriptors available to the process are currently open.
- ENAMETOOLONG
-
The length of a component of a pathname is longer than
{NAME_MAX}.
- ENAMETOOLONG
-
The length of a pathname exceeds
{PATH_MAX},
or pathname resolution of a symbolic link produced an intermediate
result with a length that exceeds
{PATH_MAX}.
- ENFILE
-
Too many files are currently open in the system.
- ENOENT
-
The message catalog does not exist or the
name
argument points to an empty string.
- ENOMEM
-
Insufficient storage space is available.
- ENOTDIR
-
A component of the path prefix of the message catalog names an existing
file that is neither a directory nor a symbolic link to a directory,
or the pathname of the message catalog contains at least one non-<slash>
character and ends with one or more trailing
<slash>
characters and the last pathname component names an existing file
that is neither a directory nor a symbolic link to a directory.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
Some implementations of
catopen()
use
malloc()
to allocate space for internal buffer areas. The
catopen()
function may fail if there is insufficient storage space available to
accommodate these buffers.
Conforming applications must assume that message catalog descriptors are
not valid after a call to one of the
exec
functions.
Application developers should be aware that guidelines for the location
of message catalogs have not yet been developed. Therefore they should
take care to avoid conflicting with catalogs used by other applications
and the standard utilities.
To be sure that messages produced by an application running with
appropriate privileges cannot be used by an attacker setting an
unexpected value for
NLSPATH
in the environment to confuse a system administrator, such
applications should use pathnames containing a
'/'
to get defined behavior when using
catopen()
to open a message catalog.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
catclose(),
catgets()
The Base Definitions volume of POSIX.1-2017,
Chapter 8, Environment Variables,
<fcntl.h>,
<nl_types.h>,
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 .
Any typographical or formatting errors that appear
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