sd_journal_get_cursor, sd_journal_test_cursor — Get cursor string for or test cursor string against the current journal entry
#include <systemd/sd-journal.h>
| int sd_journal_get_cursor( | sd_journal* j, | 
| char ** cursor ); | 
| int sd_journal_test_cursor( | sd_journal* j, | 
| const char * cursor ); | 
sd_journal_get_cursor()
                returns a cursor string for the current journal
                entry. A cursor is a serialization of the current
                journal position formatted as text. The string only
                contains printable characters and can be passed around
                in text form. The cursor identifies a journal entry
                globally and in a stable way and may be used to later
                seek to it via
                sd_journal_seek_cursor(3). The
                cursor string should be considered opaque and not be
                parsed by clients. Seeking to a cursor position
                without the specific entry being available locally
                will seek to the next closest (in terms of time)
                available entry. The call takes two arguments: a
                journal context object and a pointer to a string
                pointer where the cursor string will be placed. The
                string is allocated via libc
                malloc(3)
                and should be freed after use with
                free(3).
Note that
                sd_journal_get_cursor() will not
                work before
                sd_journal_next(3)
                (or related call) has been called at least once, in
                order to position the read pointer at a valid
                entry.
sd_journal_test_cursor()
                may be used to check whether the current position in
                the journal matches the specified cursor. This is
                useful since cursor strings do not uniquely identify
                an entry: the same entry might be referred to by
                multiple different cursor strings, and hence string
                comparing cursors is not possible. Use this call to
                verify after an invocation of
                sd_journal_seek_cursor(3)
                whether the entry being sought to was actually found
                in the journal or the next closest entry was used
                instead.
sd_journal_get_cursor()
                returns 0 on success or a negative errno-style error
                code. sd_journal_test_cursor()
                returns positive if the current entry matches the
                specified cursor, 0 if it doesn't match the specified
                cursor or a negative errno-style error code on
                failure.
The sd_journal_get_cursor()
                and sd_journal_test_cursor()
                interfaces are available as shared library, which can
                be compiled and linked to with the
                libsystemd-journal
                pkg-config(1)
                file.