x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SD_JOURNAL_OPEN(3) sd_journal_open SD_JOURNAL_OPEN(3)
NAME
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
SYNOPSIS
#include <systemd/sd-journal.h>
int sd_journal_open(sd_journal** ret, int flags);
int sd_journal_open_directory(sd_journal** ret, const char* path,
int flags);
int sd_journal_open_files(sd_journal** ret, const char** paths,
int flags);
int sd_journal_open_container(sd_journal** ret, const char* machine,
int flags);
void sd_journal_close(sd_journal* j);
DESCRIPTION
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: SD_JOURNAL_LOCAL_ONLY makes sure only journal files
generated on the local machine will be opened. 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_SYSTEM nor SD_JOURNAL_CURRENT_USER are specified, all
journal file types will be opened.
sd_journal_open_directory() is similar to 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 racy.
sd_journal_open_container() is similar to 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 systemd-machined(8).
sd_journal objects cannot be used in the child after a fork. Functions
which take a journal object as an argument (sd_journal_next() and
others) will return -ECHILD after a fork.
sd_journal_close() will close the journal context allocated with
sd_journal_open() or sd_journal_open_directory() and free its
resources.
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.
See sd_journal_next(3) for an example of how to iterate through the
journal after opening it with sd_journal_open().
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 sd_journal_next(3) and sd_journal_seek_head(3) and
related calls. The current entry position may be exported in cursor
strings, as accessible via sd_journal_get_cursor(3). 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 time) sd_journal_seek_cursor(3).
Notification of journal changes is available via sd_journal_get_fd()
and related calls.
RETURN VALUE
The sd_journal_open(), sd_journal_open_directory(), and
sd_journal_open_files() calls return 0 on success or a negative
errno-style error code. sd_journal_close() returns nothing.
NOTES
The sd_journal_open(), sd_journal_open_directory() and
sd_journal_close() interfaces are available as a shared library, which
can be compiled and linked to with the libsystemd pkg-config(1) file.
HISTORY
sd_journal_open(), sd_journal_close(), SD_JOURNAL_LOCAL_ONLY,
SD_JOURNAL_RUNTIME_ONLY, SD_JOURNAL_SYSTEM_ONLY were added in
systemd-38.
sd_journal_open_directory() was added in systemd-187.
SD_JOURNAL_SYSTEM, SD_JOURNAL_CURRENT_USER, and sd_journal_open_files()
were added in systemd-205. SD_JOURNAL_SYSTEM_ONLY was deprecated.
SEE ALSO
systemd(1), sd-journal(3), sd_journal_next(3), sd_journal_get_data(3),
systemd-machined(8)
systemd 210 SD_JOURNAL_OPEN(3)
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