CATOPEN(3)                                                              Linux Programmer's Manual                                                             CATOPEN(3)

NAME
       catopen, catclose - open/close a message catalog

SYNOPSIS
       #include <nl_types.h>

       nl_catd catopen(const char *name, int flag);
       int catclose(nl_catd catalog);

DESCRIPTION
       The function catopen() opens a message catalog and returns a catalog descriptor.  The descriptor remains valid until catclose() or execve(2).  If a file descrip‐
       tor is used to implement catalog descriptors, then the FD_CLOEXEC flag will be set.

       The argument name specifies the name of the message catalog to be opened.  If name specifies an absolute path (i.e., contains a '/'), then name specifies a path‐
       name  for  the  message  catalog.   Otherwise,  the environment variable NLSPATH is used with name substituted for %N (see locale(7)).  It is unspecified whether
       NLSPATH will be used when the process has root privileges.  If NLSPATH does not exist in the environment, or if a message catalog cannot be opened in any of  the
       paths specified by it, then an implementation defined path is used.  This latter default path may depend on the LC_MESSAGES locale setting when the flag argument
       is NL_CAT_LOCALE and on the LANG environment variable when the flag argument is 0.  Changing the LC_MESSAGES part of the locale may invalidate open  catalog  de‐
       scriptors.

       The  flag  argument to catopen() is used to indicate the source for the language to use.  If it is set to NL_CAT_LOCALE, then it will use the current locale set‐
       ting for LC_MESSAGES.  Otherwise, it will use the LANG environment variable.

       The function catclose() closes the message catalog identified by catalog.  It invalidates any subsequent references to the message catalog defined by catalog.

RETURN VALUE
       The function catopen() returns a message catalog descriptor of type nl_catd on success.  On failure, it returns (nl_catd) -1 and sets errno to indicate  the  er‐
       ror.  The possible error values include all possible values for the open(2) call.

       The function catclose() returns 0 on success, or -1 on failure.

ENVIRONMENT
       LC_MESSAGES
              May be the source of the LC_MESSAGES locale setting, and thus determine the language to use if flag is set to NL_CAT_LOCALE.

       LANG   The language to use if flag is 0.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────────┐
       │Interface                                                                                                                         │ Attribute     │ Value       │
       ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────────┤
       │catopen()                                                                                                                         │ Thread safety │ MT-Safe env │
       ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────────┤
       │catclose()                                                                                                                        │ Thread safety │ MT-Safe     │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────────┘

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

NOTES
       The  above  is  the  POSIX.1  description.   The  glibc  value  for  NL_CAT_LOCALE  is 1.  The default path varies, but usually looks at a number of places below
       /usr/share/locale.

SEE ALSO
       catgets(3), setlocale(3)

GNU                                                                            2021-03-22                                                                     CATOPEN(3)