NAME

catopen, catclose − open/close a message catalog

SYNOPSIS

#include <nl_types.h>

nl_catd catopen (char ∗name, int oflag);

int catclose (nl_catd catd);

DESCRIPTION

catopen opens a message catalog and returns a catalog descriptor.  name 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.  If NLSPATH does not exist in the environment, or if a message catalog cannot be opened in any of the paths specified by NLSPATH, then the default path is used [see nl_types(5)]. 

The names of message catalogs, and their location in the filestore, can vary from one system to another.  Individual applications can choose to name or locate message catalogs according to their own special needs.  A mechanism is therefore required to specify where the catalog resides. 

The NLSPATH variable provides both the location of message catalogs, in the form of a search path, and the naming conventions associated with message catalog files.  For example:

NLSPATH=/nlslib/%L/%N.cat:/nlslib/%N/%L

The metacharacter % introduces a substitution field, where %L substitutes the current setting of the LANG environment variable (see following section), and %N substitutes the value of the name parameter passed to catopen.  Thus, in the above example, catopen will search in /nlslib/$LANG/name.cat, then in /nlslib/name/$LANG, for the required message catalog. 

NLSPATH will normally be set up on a system wide basis (for example, in /etc/profile) and thus makes the location and naming conventions associated with message catalogs transparent to both programs and users. 

The full set of metacharacters is:

%N The value of the name parameter passed to catopen. 

%L The value of LANG. 

%l The value of the language element of LANG. 

%t The value of the territory element of LANG. 

%c The value of the codeset element of LANG. 

%% A single %. 

The LANG environment variable provides the ability to specify the user’s requirements for native languages, local customs and character set, as an ASCII string in the form

LANG=language[_territory[.codeset]]

A user who speaks German as it is spoken in Austria and has a terminal which operates in ISO 8859/1 codeset, would want the setting of the LANG variable to be

LANG=De_A.88591

With this setting it should be possible for that user to find any relevant catalogs should they exist. 

Should the LANG variable not be set then the value of LC_MESSAGES as returned by setlocale is used.  If this is NULL then the default path as defined in nl_types is used. 

oflag is reserved for future use and should be set to 0.  The results of setting this field to any other value are undefined. 

catclose closes the message catalog identified by catd.

SEE ALSO

catgets(3C), setlocale(3C), environ(5), nl_types(5)

DIAGNOSTICS

If successful, catopen returns a message catalog descriptor for use on ­subsequent calls to catgets and catclose.  Otherwise catopen returns
(nl_catd) -1. 

catclose returns 0 if successful, otherwise −1.