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 complete name 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
IEEE Std 1003.1-2001, 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 IEEE Std 1003.1-2001, 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 {OPEN_MAX} file descriptors are currently open in the calling
process.
ENAMETOOLONG
The length of a pathname of the message catalog exceeds
{PATH_MAX} or a pathname component is longer than {NAME_MAX}.
ENAMETOOLONG
Pathname resolution of a symbolic link produced an intermediate
result whose length 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 is not 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 writers 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.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
catclose() , catgets() , the Base Definitions volume of
IEEE Std 1003.1-2001, <fcntl.h>, <nl_types.h>, the Shell and Utilities
volume of IEEE Std 1003.1-2001
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .