sd_journal_open, sd_journal_open_directory, sd_journal_open_files, sd_journal_open_container, sd_journal_close, sd_journal, SD_JOURNAL_LOCAL_ONLY, SD_JOURNAL_RUNTIME_ONLY, SD_JOURNAL_SYSTEM, SD_JOURNAL_CURRENT_USER — Open the system journal for reading
|const char *path,|
|const char **paths,|
|const char *machine,|
sd_journal_open() opens the log journal
for reading. It will find all journal files automatically and
interleave them automatically when reading. As first argument it
takes a pointer to a
sd_journal pointer, which,
on success, will contain a journal context object. The second
argument is a flags field, which may consist of the following
flags ORed together:
makes sure only journal files generated on the local machine will
SD_JOURNAL_RUNTIME_ONLY makes sure
only volatile journal files will be opened, excluding those which
are stored on persistent storage.
SD_JOURNAL_SYSTEM will cause journal files of
system services and the kernel (in opposition to user session
processes) to be opened.
SD_JOURNAL_CURRENT_USER will cause journal
files of the current user to be opened. If neither
SD_JOURNAL_CURRENT_USER are specified, all
journal file types will be opened.
sd_journal_open_directory() is similar
sd_journal_open() but takes an absolute
directory path as argument. All journal files in this directory
will be opened and interleaved automatically. This call also takes
a flags argument, but it must be passed as 0 as no flags are
currently understood for this call.
sd_journal_open_files() is similar to
sd_journal_open() but takes a
NULL-terminated list of file paths to open.
All files will be opened and interleaved automatically. This call
also takes a flags argument, but it must be passed as 0 as no
flags are currently understood for this call. Please note that in
the case of a live journal, this function is only useful for
debugging, because individual journal files can be rotated at any
moment, and the opening of specific files is inherently
sd_journal_open_container() is similar
sd_journal_open() but opens the journal
files of a running OS container. The specified machine name refers
to a container that is registered with
sd_journal objects cannot be used in the
child after a fork. Functions which take a journal object as an
sd_journal_next() and others) will
-ECHILD after a fork.
sd_journal_close() will close the
journal context allocated with
sd_journal_open_directory() and free its
When opening the journal only journal files accessible to the calling user will be opened. If journal files are not accessible to the caller, this will be silently ignored.
for an example of how to iterate through the journal after opening
A journal context object returned by
sd_journal_open() references a specific
journal entry as current entry, similar to a
file seek index in a classic file system file, but without
absolute positions. It may be altered with
and related calls. The current entry position may be exported in
cursor strings, as accessible via
Cursor strings may be used to globally identify a specific journal
entry in a stable way and then later to seek to it (or if the
specific entry is not available locally, to its closest entry in
Notification of journal changes is available via
sd_journal_get_fd() and related calls.
sd_journal_open_files() calls return 0 on
success or a negative errno-style error code.
sd_journal_close() returns nothing.
sd_journal_close() interfaces are available
as a shared library, which can be compiled and linked to with the
SD_JOURNAL_SYSTEM_ONLY were added in
sd_journal_open_directory() was added
sd_journal_open_files() were added in