From f2f1f2472c5efc541bd53f51289ad58a86fa2d41 Mon Sep 17 00:00:00 2001 From: Luke Shumaker Date: Sat, 20 May 2017 17:35:06 -0400 Subject: ./tools/notsd-move --- src/libsystemd/sd_journal_enumerate_fields.xml | 164 +++++++++++++++++++++++++ 1 file changed, 164 insertions(+) create mode 100644 src/libsystemd/sd_journal_enumerate_fields.xml (limited to 'src/libsystemd/sd_journal_enumerate_fields.xml') diff --git a/src/libsystemd/sd_journal_enumerate_fields.xml b/src/libsystemd/sd_journal_enumerate_fields.xml new file mode 100644 index 0000000000..bc2c21ed4b --- /dev/null +++ b/src/libsystemd/sd_journal_enumerate_fields.xml @@ -0,0 +1,164 @@ + + + + + + + + + sd_journal_enumerate_fields + systemd + + + + Developer + Lennart + Poettering + lennart@poettering.net + + + + + + sd_journal_enumerate_fields + 3 + + + + sd_journal_enumerate_fields + sd_journal_restart_fields + SD_JOURNAL_FOREACH_FIELD + Read used field names from the journal + + + + + #include <systemd/sd-journal.h> + + + int sd_journal_enumerate_fields + sd_journal *j + const char **field + + + + void sd_journal_restart_fields + sd_journal *j + + + + SD_JOURNAL_FOREACH_FIELD + sd_journal *j + const char *field + + + + + + + Description + + sd_journal_enumerate_fields() may be used to iterate through all field names used in the + opened journal files. On each invocation the next field name is returned. The order of the returned field names is + not defined. It takes two arguments: the journal context object, plus a pointer to a constant string pointer where + the field name is stored in. The returned data is in a read-only memory map and is only valid until the next + invocation of sd_journal_enumerate_fields(). Note that this call is subject to the data field + size threshold as controlled by sd_journal_set_data_threshold(). + + sd_journal_restart_fields() resets the field name enumeration index to the beginning of + the list. The next invocation of sd_journal_enumerate_fields() will return the first field + name again. + + The SD_JOURNAL_FOREACH_FIELD() macro may be used as a handy wrapper around + sd_journal_restart_fields() and sd_journal_enumerate_fields(). + + These functions currently are not influenced by matches set with sd_journal_add_match() + but this might change in a later version of this software. + + To retrieve the possible values a specific field can take use + sd_journal_query_unique3. + + + + Return Value + + sd_journal_enumerate_fields() returns a + positive integer if the next field name has been read, 0 when no + more field names are known, or a negative errno-style error code. + sd_journal_restart_fields() returns + nothing. + + + + Notes + + All functions listed here are thread-agnostic and only a single thread may operate + on a given sd_journal object. + + The sd_journal_enumerate_fields() and sd_journal_restart_fields() + interfaces are available as a shared library, which can be compiled and linked to with the + libsystemd pkg-config1 file. + + + + Examples + + Use the SD_JOURNAL_FOREACH_FIELD macro to iterate through all field names in use in the + current journal. + + #include <stdio.h> +#include <string.h> +#include <systemd/sd-journal.h> + +int main(int argc, char *argv[]) { + sd_journal *j; + const char *field; + int r; + + r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY); + if (r < 0) { + fprintf(stderr, "Failed to open journal: %s\n", strerror(-r)); + return 1; + } + SD_JOURNAL_FOREACH_FIELD(j, field) + printf("%s\n", field); + sd_journal_close(j); + return 0; +} + + + + + See Also + + + systemd1, + systemd.journal-fields7, + sd-journal3, + sd_journal_open3, + sd_journal_query_unique3, + sd_journal_get_data3, + sd_journal_add_match3 + + + + -- cgit v1.2.3-54-g00ecf