открыть каталог сообщений (open a message catalog)
Пролог (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.
Имя (Name)
catopen — open a message catalog
Синопсис (Synopsis)
#include <nl_types.h>
nl_catd catopen(const char *name, int oflag);
Описание (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).
Возвращаемое значение (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.
Ошибки (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.
Примеры (Examples)
None.
Использование в приложениях (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.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
catclose(3p), catgets(3p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, fcntl.h(0p), nl_types.h(0p),
