catopen - open message catalog

Syntax	#include <nl_types.h> nl_catd catopen(const char *name, int oflag);
Description	catopen() opens a message catalog and returns a message catalog descriptor. The name argument specifies the name of the message catalog to be opened. If name contains a "/", then name is interpreted as an absolute pathname for the message catalog. Otherwise, the environment variable NLSPATH is evaluated and used with name substituted for %N (see also section “Locale”). If the environment variable NLSPATH does not exist or if a message catalog cannot be found in any of the path components specified by NLSPATH, then the default path is used (see nl_types.h). If the value of oflag is NL_CAT_LOCALE, the default is determined by the category LC_MESSAGES. If oflag is 0, only the LANG environment variable is evaluated, regardless of the contents of the LC_MESSAGES category (see also section “Environment variables”). A message catalog descriptor remains valid in a process until it is closed by that process or by a successful call to one of the exec functions. A change in the LC_MESSAGES category can make existing open catalogs invalid. If a file descriptor is used to define message catalog descriptors, the FD_CLOEXEC bit is set (see also fcntl.h).
Return val.	Message catalog descriptor if successful. This message catalog descriptor can then be used on subsequent calls to catgets() and catclose(). (nl_catd) -1 if unsuccessful. errno is set to indicate the error.

Errors	catopen() will fail if:
	EACCES	Search permission is denied for a component of the path prefix of the message catalog or read permission is denied for the message catalog.
	EMFILE	The process uses more than {OPEN_MAX} file descriptors at one time.
	ENAMETOOLONG
		The length of the pathname of the message catalog exceeds {PATH_MAX}, or a pathname component is longer than {NAME_MAX}, or the resolution of a symbolic link produces an interim result that is longer than {PATH_MAX}.
	ENFILE ENOENT	Too many files are currently open in the system. The message catalog does not exist, or the name argument points to an empty string
	ENOMEM ENOTDIR	Insufficient storage space is available. A component of the path prefix of the message catalog is not a directory.
Notes	catopen() uses malloc() to allocate space for internal buffer areas. The catopen() function may fail if there is insufficient storage space available to accommodate these buffers. Portable applications must assume that message catalog descriptors are not valid after a call to one of the exec functions. Every application must store the associated message catalog in one of the default directories defined by DEF_NLSPATH in a format that allows it to be found on substitution of name for %N (see also nl_types.h).
See also	catclose(), catgets(), fcntl.h, nl_types.h, section “Locale” and section “Environment variables”.