.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "CATOPEN" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" catopen 
.SH 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.
.SH NAME
catopen \- open a message catalog
.SH SYNOPSIS
.LP
\fB#include <nl_types.h>
.br
.sp
nl_catd catopen(const char *\fP\fIname\fP\fB, int\fP \fIoflag\fP\fB);
\fP
\fB
.br
\fP
.SH DESCRIPTION
.LP
The \fIcatopen\fP() function shall open a message catalog and return
a message catalog descriptor. The \fIname\fP argument
specifies the name of the message catalog to be opened. If \fIname\fP
contains a \fB'/'\fP, then \fIname\fP specifies a
complete name for the message catalog. Otherwise, the environment
variable \fINLSPATH\fP is used with \fIname\fP substituted for
the \fB%N\fP conversion specification (see the Base Definitions volume
of IEEE\ Std\ 1003.1-2001, Chapter 8, Environment Variables). If \fINLSPATH\fP
exists in the environment when the process
starts, then if the process has appropriate privileges, the behavior
of \fIcatopen\fP() is undefined. If \fINLSPATH\fP does not
exist in the environment, or if a message catalog cannot be found
in any of the components specified by \fINLSPATH\fP, then an
implementation-defined default path shall be used. This default may
be affected by the setting of \fILC_MESSAGES\fP if the value
of \fIoflag\fP is NL_CAT_LOCALE, or the \fILANG\fP environment variable
if \fIoflag\fP is 0.
.LP
A message catalog descriptor shall remain valid in a process until
that process closes it, or a successful call to one of the
\fIexec\fP functions. A change in the setting of the \fILC_MESSAGES\fP
category may
invalidate existing open catalogs.
.LP
If a file descriptor is used to implement message catalog descriptors,
the FD_CLOEXEC flag shall be set; see \fI<fcntl.h>\fP.
.LP
If the value of the \fIoflag\fP argument is 0, the \fILANG\fP environment
variable is used to locate the catalog without
regard to the \fILC_MESSAGES\fP category. If the \fIoflag\fP argument
is NL_CAT_LOCALE, the \fILC_MESSAGES\fP category is used
to locate the message catalog (see the Base Definitions volume of
IEEE\ Std\ 1003.1-2001, Section 8.2, Internationalization Variables).
.SH RETURN VALUE
.LP
Upon successful completion, \fIcatopen\fP() shall return a message
catalog descriptor for use on subsequent calls to \fIcatgets\fP()
and \fIcatclose\fP(). Otherwise,
\fIcatopen\fP() shall return ( \fBnl_catd\fP) -1 and set \fIerrno\fP
to indicate the error.
.SH ERRORS
.LP
The \fIcatopen\fP() function may fail if:
.TP 7
.B 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.
.TP 7
.B EMFILE
{OPEN_MAX} file descriptors are currently open in the calling process.
.TP 7
.B ENAMETOOLONG
The length of a pathname of the message catalog exceeds {PATH_MAX}
or a pathname component is longer than {NAME_MAX}.
.TP 7
.B ENAMETOOLONG
Pathname resolution of a symbolic link produced an intermediate result
whose length exceeds {PATH_MAX}.
.TP 7
.B ENFILE
Too many files are currently open in the system.
.TP 7
.B ENOENT
The message catalog does not exist or the \fIname\fP argument points
to an empty string.
.TP 7
.B ENOMEM
Insufficient storage space is available.
.TP 7
.B ENOTDIR
A component of the path prefix of the message catalog is not a directory.
.sp
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
Some implementations of \fIcatopen\fP() use \fImalloc\fP() to allocate
space for
internal buffer areas. The \fIcatopen\fP() function may fail if there
is insufficient storage space available to accommodate these
buffers.
.LP
Conforming applications must assume that message catalog descriptors
are not valid after a call to one of the \fIexec\fP functions.
.LP
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.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIcatclose\fP(), \fIcatgets\fP(), the Base Definitions volume of
IEEE\ Std\ 1003.1-2001, \fI<fcntl.h>\fP, \fI<nl_types.h>\fP, the Shell
and Utilities volume of IEEE\ Std\ 1003.1-2001
.SH 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 .