# sd_journal_seek_head

## NAME



           sd_journal_seek_head, sd_journal_seek_tail,
           sd_journal_seek_monotonic_usec, sd_journal_seek_realtime_usec,
           sd_journal_seek_cursor - Seek to a position in the journal
    


## SYNOPSIS



           **#include <systemd/sd-journal.h>**
    
           **int sd_journal_seek_head(sd_journal ***_j_**);**
    
           **int sd_journal_seek_tail(sd_journal ***_j_**);**
    
           **int sd_journal_seek_monotonic_usec(sd_journal ***_j_**,**
                                              **sd_id128_t** _boot_id_**,**
                                              **uint64_t** _usec_**);**
    
           **int sd_journal_seek_realtime_usec(sd_journal ***_j_**, uint64_t** _usec_**);**
    
           **int sd_journal_seek_cursor(sd_journal ***_j_**, const char ***_cursor_**);**
    


## DESCRIPTION



           **sd_journal_seek_head()** seeks to the beginning of the journal, i.e.
           to the position before the oldest available entry.
    
           Similarly, **sd_journal_seek_tail()** may be used to seek to the end
           of the journal, i.e. the position after the most recent available
           entry.
    
           **sd_journal_seek_monotonic_usec()** seeks to a position with the
           specified monotonic timestamp, i.e.  **CLOCK_MONOTONIC**. Since
           monotonic time restarts on every reboot a boot ID needs to be
           specified as well.
    
           **sd_journal_seek_realtime_usec()** seeks to a position with the
           specified realtime (wallclock) timestamp, i.e.  **CLOCK_REALTIME**.
           Note that the realtime clock is not necessarily monotonic. If a
           realtime timestamp is ambiguous, it is not defined which position
           is sought to.
    
           **sd_journal_seek_cursor()** seeks to the position at the specified
           cursor string. For details on cursors, see
           sd_journal_get_cursor(3). If no entry matching the specified
           cursor is found the call will seek to the next closest entry (in
           terms of time) instead.
    
           Note that these calls do not actually make any entry the new
           current entry, this needs to be done in a separate step with a
           subsequent sd_journal_next(3) invocation (or a similar call). Only
           then, entry data may be retrieved via sd_journal_get_data(3) or an
           entry cursor be retrieved via sd_journal_get_cursor(3). If no
           entry exists that matches exactly the specified seek address, the
           next closest is sought to. If sd_journal_next(3) is used, the
           closest following entry will be sought to, if
           sd_journal_previous(3) is used the closest preceding entry is
           sought to.
    
           After the seek is done, and sd_journal_next(3) or a similar call
           has been made, sd_journal_test_cursor(3) may be used to verify
           whether the newly selected entry actually matches the cursor.
    


## RETURN VALUE



           The functions return 0 on success or a negative errno-style error
           code.
    


## NOTES



           All functions listed here are thread-agnostic and only a single
           specific thread may operate on a given object during its entire
           lifetime. It is safe to allocate multiple independent objects and
           use each from a specific thread in parallel. However, it is not
           safe to allocate such an object in one thread, and operate or free
           it from any other, even if locking is used to ensure these threads
           do not operate on it at the very same time.
    
           Functions described here are available as a shared library, which
           can be compiled against and linked to with the
           **libsystemd pkg-config**(1) file.
    


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