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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.

DESCRIPTION top

Thecatopen() function shall open a message catalog and return a message catalog descriptor. Thename argument specifies the name of the message catalog to be opened. Ifname contains a'/', thenname specifies a pathname for the message catalog. Otherwise, the environment variableNLSPATH is used withname substituted for the%Nconversion specification (see the Base Definitions volume of POSIX.1‐2017,Chapter 8,Environment Variables); ifNLSPATH exists in the environment when the process starts, then if the process has appropriate privileges, the behavior ofcatopen() is undefined. IfNLSPATH does not exist in the environment, or if a message catalog cannot be found in any of the components specified byNLSPATH, then an implementation-defined default path shall be used. This default may be affected by the setting ofLC_MESSAGES if the value ofoflag is NL_CAT_LOCALE, or theLANG environment variable ifoflag is 0. A message catalog descriptor shall remain valid in a process until that process closes it, or a successful call to one of theexec functions. A change in the setting of theLC_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 theoflag argument is 0, theLANG environment variable is used to locate the catalog without regard to theLC_MESSAGES category. If theoflag argument is NL_CAT_LOCALE, theLC_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 tocatgets() andcatclose(). Otherwise,catopen() shall return (nl_catd) -1 and seterrno to indicate the error.

ERRORS top

Thecatopen() function may fail if:EACCESSearch permission is denied for the component of the path prefix of the message catalog or read permission is denied for the message catalog.EMFILEAll 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}.ENFILEToo many files are currently open in the system.ENOENTThe message catalog does not exist or thename argument points to an empty string.ENOMEMInsufficient 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.

APPLICATION USAGE top

Some implementations ofcatopen() usemalloc() to allocate space for internal buffer areas. Thecatopen() 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 theexec 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 forNLSPATH in the environment to confuse a system administrator, such applications should use pathnames containing a'/'to get defined behavior when usingcatopen() to open a message catalog.

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 athttp://www.opengroup.org/unix/online.html . 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, seehttps://www.kernel.org/doc/man-pages/reporting_bugs.html .IEEE/The Open Group 2017CATOPEN(3P)

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