catopen

CATOPEN(3)                                                          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  exec().
       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 environ-
       ment, 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 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  cata-
       log.   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() 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.

NOTES
       The above is the POSIX 1003.1-2001 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.

NOTES FOR LIBC4 AND LIBC5
       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()'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.

CONFORMING TO
       POSIX  1003.1-2001.   In XPG 1987, Vol. 3 it says: The flag argument of
       catopen is reserved for future use and should  be  set  to  0.   It  is
       unclear  what  the source was for the constants MCLoadBySet and MCLoad-
       All.

SEE ALSO
       catgets(3), setlocale(3)



                                  2001-12-14                        CATOPEN(3)