SD_JOURNAL_GET_CURSOR(3)sd_journal_get_cursorSD_JOURNAL_GET_CURSOR(3)NAME
sd_journal_get_cursor, sd_journal_test_cursor - Get cursor string for
or test cursor string against the current journal entry
SYNOPSIS
#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);
DESCRIPTIONsd_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.
RETURN VALUEsd_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 does not match the
specified cursor or a negative errno-style error code on failure.
NOTES
The sd_journal_get_cursor() and sd_journal_test_cursor() interfaces are
available as a shared library, which can be compiled and linked to with
the libsystemd-journal pkg-config(1) file.
SEE ALSOsystemd(1), sd-journal(3), sd_journal_open(3),
sd_journal_seek_cursor(3)systemd 208SD_JOURNAL_GET_CURSOR(3)
