systemd Developer Lennart Poettering lennart@poettering.net sd_journal_get_cursor 3 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_cursor3. 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 malloc3 and should be freed after use with free3. Note that sd_journal_get_cursor() will not work before sd_journal_next3 (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_cursor3 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-config1 file. systemd1, sd-journal3, sd_journal_open3, sd_journal_seek_cursor3