systemd/man/sd_journal_stream_fd.xml
Thomas Hindoe Paaboel Andersen bb31a4ac19 man: typo fixes
https://bugs.freedesktop.org/show_bug.cgi?id=55890

Fixed typos, serial comma, and removed "either" as there were more
than two options. Also did an extra rename of "system-shutdown"
to "systemd-shutdown" that was forgotten in commit
8bd3b8620c
2012-10-26 00:16:47 +02:00

172 lines
7.2 KiB
XML

<?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">
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<refentry id="sd_journal_stream_fd">
<refentryinfo>
<title>sd_journal_stream_fd</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_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 STDOUT/STDERR 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 <literal>LOG_EMERG</literal>,
<literal>LOG_ALERT</literal>,
<literal>LOG_CRIT</literal>,
<literal>LOG_ERR</literal>,
<literal>LOG_WARNING</literal>,
<literal>LOG_NOTICE</literal>,
<literal>LOG_INFO</literal>,
<literal>LOG_DEBUG</literal>, as defined in
<filename>syslog.h</filename>, see
<citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for details. The third argument is a boolean: if true
kernel-style log priority level prefixes (such as
<literal>SD_WARNING</literal>) 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>
</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>Notes</title>
<para>The <function>sd_journal_stream_fd()</function>
interface is available as shared library, which can
be compiled and linked to with the
<literal>libsystemd-journal</literal>
<citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>Creating a log stream suitable for
<citerefentry><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><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>fprintf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>