catopen(3p) — Linux manual page


CATOPEN(3P)             POSIX Programmer's Manual            CATOPEN(3P)

PROLOG         top

       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         top

       catopen — open a message catalog

SYNOPSIS         top

       #include <nl_types.h>

       nl_catd catopen(const char *name, int oflag);

DESCRIPTION         top

       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         top

       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         top

       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.

              The length of a component of a pathname is longer than

              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.

              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         top



       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

       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         top




SEE ALSO         top

       catclose(3p), catgets(3p)

       The Base Definitions volume of POSIX.1‐2017, Chapter 8,
       Environment Variables, fcntl.h(0p), nl_types.h(0p),

COPYRIGHT         top

       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 .

       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 .

IEEE/The Open Group               2017                       CATOPEN(3P)

Pages that refer to this page: nl_types.h(0p)catclose(3p)catgets(3p)setlocale(3p)