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 cat-
       close() or execve(2).  If a file descriptor 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 and absolute path (i.e.,
       contains a '/'), then name specifies a pathname 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_MES-
       SAGES 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 descriptors.

       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 setting 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 error.  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.

CONFORMING TO
       POSIX.1-2001.  It is unclear what the source was for the constants MCLoadBySet and MCLoadAll (see below).

NOTES
       The above is the POSIX.1-2001 description.  The glibc value for NL_CAT_LOCALE is  1.   (Compare  MCLoadAll  below.)   The
       default path varies, but usually looks at a number of places below /usr/share/locale.

   Linux Notes
       These  functions are available for Linux since libc 4.4.4c.  In the case of linux libc4 and libc5, the catalog descriptor
       nl_catd is a mmap(2)'ed area of memory and not a file descriptor.  The  flag  argument  to  catopen()  should  be  either
       MCLoadBySet  (=0) or MCLoadAll (=1).  The former value indicates that a set from the catalog is to be loaded when needed,
       whereas the latter causes the initial call to catopen() to load the entire catalog into memory.  The default search  path
       varies, but usually looks at a number of places below /etc/locale and /usr/lib/locale.

SEE ALSO
       catgets(3), setlocale(3)

COLOPHON
       This  page  is  part of release 3.25 of the Linux man-pages project.  A description of the project, and information about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



GNU                                                        2001-12-14                                                 CATOPEN(3)