diff options
Diffstat (limited to 'man/sd_journal_next.xml')
| -rw-r--r-- | man/sd_journal_next.xml | 352 |
1 files changed, 173 insertions, 179 deletions
diff --git a/man/sd_journal_next.xml b/man/sd_journal_next.xml index 4df6b4e6fd..115fe26661 100644 --- a/man/sd_journal_next.xml +++ b/man/sd_journal_next.xml @@ -1,6 +1,6 @@ <?xml version='1.0'?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" - "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. @@ -23,191 +23,185 @@ <refentry id="sd_journal_next"> - <refentryinfo> - <title>sd_journal_next</title> - <productname>systemd</productname> - - <authorgroup> - <author> - <contrib>Developer</contrib> - <firstname>Lennart</firstname> - <surname>Poettering</surname> - <email>lennart@poettering.net</email> - </author> - </authorgroup> - </refentryinfo> - - <refmeta> - <refentrytitle>sd_journal_next</refentrytitle> - <manvolnum>3</manvolnum> - </refmeta> - - <refnamediv> - <refname>sd_journal_next</refname> - <refname>sd_journal_previous</refname> - <refname>sd_journal_next_skip</refname> - <refname>sd_journal_previous_skip</refname> - <refname>SD_JOURNAL_FOREACH</refname> - <refname>SD_JOURNAL_FOREACH_BACKWARDS</refname> - <refpurpose>Advance or set back the read pointer in the journal</refpurpose> - </refnamediv> - - <refsynopsisdiv> - <funcsynopsis> - <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> - - <funcprototype> - <funcdef>int <function>sd_journal_next</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_journal_previous</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_journal_next_skip</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - <paramdef>uint64_t <parameter>skip</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_journal_previous_skip</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - <paramdef>uint64_t <parameter>skip</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef><function>SD_JOURNAL_FOREACH</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef><function>SD_JOURNAL_FOREACH_BACKWARDS</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - </funcprototype> - </funcsynopsis> - </refsynopsisdiv> - - <refsect1> - <title>Description</title> - - <para><function>sd_journal_next()</function> advances - the read pointer into the journal by one entry. The - only argument taken is a journal context object as - allocated via - <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>. After - successful invocation the entry may be read with - functions such as - <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> - - <para>Similarly, <function>sd_journal_previous()</function> sets - the read pointer back one entry.</para> - - <para><function>sd_journal_next_skip()</function> and - <function>sd_journal_previous_skip()</function> - advance/set back the read pointer by multiple entries - at once, as specified in the <varname>skip</varname> - parameter.</para> - - <para>The journal is strictly ordered by reception - time, and hence advancing to the next entry guarantees - that the entry then pointing to is later in time than - then previous one, or has the same timestamp.</para> - - <para>Note that - <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry> - and related calls will fail unless - <function>sd_journal_next()</function> has been - invoked at least once in order to position the read - pointer on a journal entry.</para> - - <para>Note that the - <function>SD_JOURNAL_FOREACH()</function> macro may be used - as a wrapper around - <citerefentry><refentrytitle>sd_journal_seek_head</refentrytitle><manvolnum>3</manvolnum></citerefentry> - and <function>sd_journal_next()</function> in order to - make iterating through the journal easier. See below - for an example. Similarly, - <function>SD_JOURNAL_FOREACH_BACKWARDS()</function> - may be used for iterating the journal in reverse - order.</para> - </refsect1> - - <refsect1> - <title>Return Value</title> - - <para>The four calls return the number of entries - advanced/set back on success or a negative errno-style - error code. When the end or beginning of the journal - is reached, a number smaller than requested is - returned. More specifically, if - <function>sd_journal_next()</function> or - <function>sd_journal_previous()</function> reach the - end/beginning of the journal they will return 0, - instead of 1 when they are successful. This should be - considered an EOF marker.</para> - </refsect1> - - <refsect1> - <title>Notes</title> - - <para>The <function>sd_journal_next()</function>, <function>sd_journal_previous()</function>, - <function>sd_journal_next_skip()</function> and - <function>sd_journal_previous_skip()</function> interfaces are - available as a shared library, which can be compiled and - linked to with the - <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> - file.</para> - </refsect1> - - <refsect1> - <title>Examples</title> - - <para>Iterating through the journal:</para> - - <programlisting>#include <stdio.h> + <refentryinfo> + <title>sd_journal_next</title> + <productname>systemd</productname> + + <authorgroup> + <author> + <contrib>Developer</contrib> + <firstname>Lennart</firstname> + <surname>Poettering</surname> + <email>lennart@poettering.net</email> + </author> + </authorgroup> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_journal_next</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_journal_next</refname> + <refname>sd_journal_previous</refname> + <refname>sd_journal_next_skip</refname> + <refname>sd_journal_previous_skip</refname> + <refname>SD_JOURNAL_FOREACH</refname> + <refname>SD_JOURNAL_FOREACH_BACKWARDS</refname> + <refpurpose>Advance or set back the read pointer in the journal</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_journal_next</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_previous</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_next_skip</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + <paramdef>uint64_t <parameter>skip</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_previous_skip</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + <paramdef>uint64_t <parameter>skip</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef><function>SD_JOURNAL_FOREACH</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef><function>SD_JOURNAL_FOREACH_BACKWARDS</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_journal_next()</function> advances the read + pointer into the journal by one entry. The only argument taken is + a journal context object as allocated via + <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + After successful invocation the entry may be read with functions + such as + <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> + + <para>Similarly, <function>sd_journal_previous()</function> sets + the read pointer back one entry.</para> + + <para><function>sd_journal_next_skip()</function> and + <function>sd_journal_previous_skip()</function> advance/set back + the read pointer by multiple entries at once, as specified in the + <varname>skip</varname> parameter.</para> + + <para>The journal is strictly ordered by reception time, and hence + advancing to the next entry guarantees that the entry then + pointing to is later in time than then previous one, or has the + same timestamp.</para> + + <para>Note that + <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry> + and related calls will fail unless + <function>sd_journal_next()</function> has been invoked at least + once in order to position the read pointer on a journal + entry.</para> + + <para>Note that the <function>SD_JOURNAL_FOREACH()</function> + macro may be used as a wrapper around + <citerefentry><refentrytitle>sd_journal_seek_head</refentrytitle><manvolnum>3</manvolnum></citerefentry> + and <function>sd_journal_next()</function> in order to make + iterating through the journal easier. See below for an example. + Similarly, <function>SD_JOURNAL_FOREACH_BACKWARDS()</function> may + be used for iterating the journal in reverse order.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>The four calls return the number of entries advanced/set + back on success or a negative errno-style error code. When the end + or beginning of the journal is reached, a number smaller than + requested is returned. More specifically, if + <function>sd_journal_next()</function> or + <function>sd_journal_previous()</function> reach the end/beginning + of the journal they will return 0, instead of 1 when they are + successful. This should be considered an EOF marker.</para> + </refsect1> + + <refsect1> + <title>Notes</title> + + <para>The <function>sd_journal_next()</function>, + <function>sd_journal_previous()</function>, + <function>sd_journal_next_skip()</function> and + <function>sd_journal_previous_skip()</function> interfaces are + available as a shared library, which can be compiled and linked to + with the + <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> + file.</para> + </refsect1> + + <refsect1> + <title>Examples</title> + + <para>Iterating through the journal:</para> + + <programlisting>#include <stdio.h> #include <string.h> #include <systemd/sd-journal.h> int main(int argc, char *argv[]) { - int r; - sd_journal *j; - 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(j) { - const char *d; - size_t l; - - r = sd_journal_get_data(j, "MESSAGE", (const void **)&d, &l); - if (r < 0) { - fprintf(stderr, "Failed to read message field: %s\n", strerror(-r)); - continue; - } - - printf("%.*s\n", (int) l, d); - } - sd_journal_close(j); - return 0; + int r; + sd_journal *j; + 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(j) { + const char *d; + size_t l; + + r = sd_journal_get_data(j, "MESSAGE", (const void **)&d, &l); + if (r < 0) { + fprintf(stderr, "Failed to read message field: %s\n", strerror(-r)); + continue; + } + + printf("%.*s\n", (int) l, d); + } + sd_journal_close(j); + return 0; }</programlisting> - </refsect1> + </refsect1> - <refsect1> - <title>See Also</title> + <refsect1> + <title>See Also</title> - <para> - <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_journal_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry> - </para> - </refsect1> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> </refentry> |