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.
catopen — open a message catalog
#include <nl_types.h>
nl_catd catopen(const char * name, int oflag);
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).
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.
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.
None.
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.
None.
None.
catclose(),
catgets()
The Base Definitions volume of POSIX.1‐2017,
Chapter 8,
Environment Variables,
<fcntl.h>,
<nl_types.h>,
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 .
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https://www.kernel.org/doc/man-pages/reporting_bugs.html .