sd-journal(3) APIs for submitting and querying log entries to and from the journal


#include <systemd/sd-journal.h>

pkg-config --cflags --libs libsystemd


sd-journal.h provides APIs to submit and query log entries. The APIs exposed act both as client for the systemd-journald.service(8) journal service and as parser for the journal files on disk.

See sd_journal_print(3), sd_journal_stream_fd(3), sd_journal_open(3), sd_journal_next(3), sd_journal_get_realtime_usec(3), sd_journal_add_match(3), sd_journal_seek_head(3), sd_journal_query_enumerate(3), sd_journal_enumerate_fields(3), sd_journal_get_cursor(3), sd_journal_get_cutoff_realtime_usec(3), sd_journal_get_cutoff_monotonic_usec(3), sd_journal_get_usage(3), sd_journal_get_catalog(3), sd_journal_get_fd(3), sd_journal_has_runtime_files(3) and sd_journal_has_persistent_files(3) for more information about the functions implemented.

Command line access for submitting entries to the journal is available with the systemd-cat(1) tool. Command line access for querying entries from the journal is available with the journalctl(1) tool.


These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.