<?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">
-
-<!--
- This file is part of systemd.
-
- Copyright 2012 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
--->
-
-<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 <systemd/sd-journal.h></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><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
- <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>
-
- </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 a shared library, which can
- be compiled and linked to with the
- <constant>libsystemd</constant> <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 <syslog.h>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//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 <systemd/sd-journal.h></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 <syslog.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <systemd/sd-daemon.h>
int main(int argc, char *argv[]) {
- int fd;
- FILE *log;
- fd = sd_journal_stream_fd("test", LOG_INFO, 1);
- if (fd < 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;
+ int fd;
+ FILE *log;
+ fd = sd_journal_stream_fd("test", LOG_INFO, 1);
+ if (fd < 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>
-
- <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>
+ </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>
projects / thirdparty / systemd.git / blobdiff