catopen(3C)						   Standard C Library Functions 					       catopen(3C)

NAME

       catopen, catclose - open/close a message catalog

SYNOPSIS

       #include <nl_types.h>

       nl_catd catopen(const char *name, int oflag);

       int catclose(nl_catd catd);

DESCRIPTION

       The  catopen() function opens a message catalog and returns a message catalog descriptor. name specifies the name of the message catalog to
       be opened. If name contains a "/", then	name specifies a complete pathname for the message catalog; otherwise,	the  environment  variable
       NLSPATH	is  used and  /usr/lib/locale/locale/LC_MESSAGES must exist. 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 /usr/lib/locale/locale/LC_MESSAGES is  used.  In  the  "C"
       locale,	catopen() will always succeed without checking the default search path.

       The  names of message catalogs and their location in the filesystem 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 either the LANG environment  variable,	if
       the  value  of oflag is	0, or the LC_MESSAGES category, if the value of oflag is  NL_CAT_LOCALE, 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,  if  oflag  is	0,  or	in
       /nlslib/{LC_MESSAGES}/name.cat, if oflag is NL_CAT_LOCALE.

       The  NLSPATH  variable  will normally be set up on a system wide basis (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 or LC_MESSAGES.

       %l	The value of the language element of LANG or LC_MESSAGES.

       %t	The value of the territory element of LANG or LC_MESSAGES.

       %c	The value of the codeset element of LANG or LC_MESSAGES.

       %%	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, the value of LC_MESSAGES as returned by setlocale() is used.  If this is NULL,  the  default  path	as
       defined in <nl_types.h> is used.

       A  message catalogue descriptor remains valid in a process until that process closes it, or a successful call to one of the exec functions.
       A change in the setting of the LC_MESSAGES category may invalidate existing open catalogues.

       If a file descriptor is used to implement message catalogue descriptors, the FD_CLOEXEC flag will be set; see <fcntl.h>.

       If the value of oflag argument is 0, the  LANG environment variable is used to locate the catalogue without regard to the  LC_MESSAGES cat-
       egory.  If the oflag argument is NL_CAT_LOCALE, the LC_MESSAGES category is used to locate the message catalogue.

       The  catclose()	function  closes  the message catalog identified by catd. If a file descriptor is used to implement the type nl_catd, that
       file descriptor will be closed.

RETURN VALUES

       Upon successful completion, catopen() returns a message catalog descriptor for use on  subsequent calls to  catgets() and catclose().  Oth-
       erwise it returns (nl_catd) -1.

       Upon successful completion, catclose() returns 0. Otherwise it returns -1 and sets errno to indicate the error.

ERRORS

       The catopen() function may fail if:

       EACCES	       Search  permission is denied for the component of the path prefix of the message catalogue or read permission is denied for
		       the message catalogue.

       EMFILE	       There are OPEN_MAX file descriptors currently open in the calling process.

       ENAMETOOLONG    The length of the pathname of the message catalogue exceeds PATH_MAX, or a pathname component is longer than NAME_MAX.

       ENAMETOOLONG    Pathname resolution of a symbolic link produced an intermediate result whose length exceeds PATH_MAX.

       ENFILE	       Too many files are currently open in the system.

       ENOENT	       The message catalogue does not exist or the name argument points to an empty string.

       ENOMEM	       Insufficient storage space is available.

       ENOTDIR	       A component of the path prefix of the message catalogue is not a directory.

       The catclose() function may fail if:

       EBADF	       The catalogue descriptor is not valid.

       EINTR	       The catclose() function was interrupted by a signal.

USAGE

       The catopen() and catclose() functions can be used safely in multithreaded applications, as long as setlocale(3C) is not  being	called	to
       change the locale.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       gencat(1), catgets(3C), gettext(3C), nl_types.h(3HEAD), setlocale(3C), attributes(5), environ(5)

SunOS 5.10							    29 Dec 1996 						       catopen(3C)