nl_catd catopen(const char *name, int flag);
int catclose(nl_catd catalog);
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 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_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 catalog. It invalidates any subsequent references to the message catalog defined by catalog.
The function catclose() returns 0 on success, or -1 on failure.
| Interface | Attribute | Value |
| catopen() | Thread safety | MT-Safe env |
| catclose() | Thread safety | MT-Safe |