Retrieve message catalog entry
#include <systemd/sd-journal.h>
int sd_journal_get_catalog(sd_journal *j, char **ret); int sd_journal_get_catalog_for_message_id(sd_id128_t id, char **ret);
sd_journal_get_catalog() retrieves a message catalog entry for the current journal entry. This will look up an entry in the message catalog by using the "MESSAGE_ID=" field of the current journal entry. Before returning the entry all journal field names in the catalog entry text enclosed in "@" will be replaced by the respective field values of the current entry. If a field name referenced in the message catalog entry does not exist, in the current journal entry, the "@" will be removed, but the field name otherwise left untouched.
sd_journal_get_catalog_for_message_id() works similar to sd_journal_get_catalog() but the entry is looked up by the specified message ID (no open journal context is necessary for this), and no field substitution is performed.
For more information about the journal message catalog please refer to the \m[blue]Journal Message Catalogs\m[]\s-2\u[1]\d\s+2 documentation page.
sd_journal_get_catalog() and sd_journal_get_catalog_for_message_id() return 0 on success or a negative errno-style error code. If no matching message catalog entry is found, -ENOENT is returned.
On successful return, ret points to a new string, which must be freed with free(3).
The sd_journal_get_catalog() and sd_journal_get_catalog_for_message_id() interfaces are available as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.
Journal Message Catalogs
http://www.freedesktop.org/wiki/Software/systemd/catalog