summaryrefslogtreecommitdiffstats
path: root/man/sd_journal_stream_fd.xml
diff options
context:
space:
mode:
Diffstat (limited to 'man/sd_journal_stream_fd.xml')
-rw-r--r--man/sd_journal_stream_fd.xml149
1 files changed, 149 insertions, 0 deletions
diff --git a/man/sd_journal_stream_fd.xml b/man/sd_journal_stream_fd.xml
new file mode 100644
index 0000000..a3ff908
--- /dev/null
+++ b/man/sd_journal_stream_fd.xml
@@ -0,0 +1,149 @@
+<?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">
+
+<!--
+ SPDX-License-Identifier: LGPL-2.1+
+-->
+
+<refentry id="sd_journal_stream_fd" xmlns:xi="http://www.w3.org/2001/XInclude">
+
+ <refentryinfo>
+ <title>sd_journal_stream_fd</title>
+ <productname>systemd</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>sd_journal_stream_fd</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>sd_journal_stream_fd</refname>
+ <refpurpose>Create log stream file descriptor to the journal</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>
+
+ <funcprototype>
+ <funcdef>int <function>sd_journal_stream_fd</function></funcdef>
+ <paramdef>const char *<parameter>identifier</parameter></paramdef>
+ <paramdef>int <parameter>priority</parameter></paramdef>
+ <paramdef>int <parameter>level_prefix</parameter></paramdef>
+ </funcprototype>
+
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><function>sd_journal_stream_fd()</function> may be used to
+ create a log stream file descriptor. Log messages written to this
+ file descriptor as simple newline-separated text strings are
+ written to the journal. This file descriptor can be used
+ internally by applications or be made standard output or standard
+ error of other processes executed.</para>
+
+ <para><function>sd_journal_stream_fd()</function> takes a short
+ program identifier string as first argument, which will be written
+ to the journal as SYSLOG_IDENTIFIER= field for each log entry
+ (see
+ <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ for more information). The second argument shall be the default
+ priority level for all messages. The priority level is one of
+ <constant>LOG_EMERG</constant>, <constant>LOG_ALERT</constant>,
+ <constant>LOG_CRIT</constant>, <constant>LOG_ERR</constant>,
+ <constant>LOG_WARNING</constant>, <constant>LOG_NOTICE</constant>,
+ <constant>LOG_INFO</constant>, <constant>LOG_DEBUG</constant>, as
+ defined in <filename>syslog.h</filename>, see
+ <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details. The third argument is a boolean: if true kernel-style
+ log level prefixes (such as <constant>SD_WARNING</constant>) are
+ interpreted, see
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for more information.</para>
+
+ <para>It is recommended that applications log UTF-8 messages only
+ with this API, but this is not enforced.</para>
+
+ <para>Each invocation of <function>sd_journal_stream_fd()</function> allocates a new log stream file descriptor,
+ that is not shared with prior or later invocations. The file descriptor is write-only (its reading direction is
+ shut down), and <constant>O_NONBLOCK</constant> is turned off initially.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>The call returns a valid write-only file descriptor on
+ success or a negative errno-style error code.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Signal safety</title>
+
+ <para><function>sd_journal_stream_fd()</function> is "async signal safe" in the meaning of <citerefentry
+ project='man-pages'><refentrytitle>signal-safety</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
+
+ <xi:include href="threads-aware.xml" xpointer="safe"/>
+
+ <xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+
+ <para>Creating a log stream suitable for
+ <citerefentry project='man-pages'><refentrytitle>fprintf</refentrytitle><manvolnum>3</manvolnum></citerefentry>:</para>
+
+ <programlisting>#include &lt;syslog.h&gt;
+#include &lt;stdio.h&gt;
+#include &lt;string.h&gt;
+#include &lt;unistd.h&gt;
+#include &lt;systemd/sd-journal.h&gt;
+#include &lt;systemd/sd-daemon.h&gt;
+
+int main(int argc, char *argv[]) {
+ int fd;
+ FILE *log;
+ fd = sd_journal_stream_fd("test", LOG_INFO, 1);
+ if (fd &lt; 0) {
+ fprintf(stderr, "Failed to create stream fd: %s\n", strerror(-fd));
+ return 1;
+ }
+ log = fdopen(fd, "w");
+ if (!log) {
+ fprintf(stderr, "Failed to create file object: %m\n");
+ close(fd);
+ return 1;
+ }
+ fprintf(log, "Hello World!\n");
+ fprintf(log, SD_WARNING "This is a warning!\n");
+ fclose(log);
+ return 0;
+}</programlisting>
+
+ </refsect1>
+
+ <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-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>fprintf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>