X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsd_watchdog_enabled.xml;h=462d7c66176c6a26775eb58416df1c7156ae0152;hp=cad92df7af2450cb799058eefd881942ee34feab;hb=a09abc4ae0bdc0200324eaa0416f23ff2170ec4e;hpb=b040723ea412209e0edf54647fa5aa4287411507

diff --git a/man/sd_watchdog_enabled.xml b/man/sd_watchdog_enabled.xml
index cad92df7a..462d7c661 100644
--- a/man/sd_watchdog_enabled.xml
+++ b/man/sd_watchdog_enabled.xml
@@ -21,7 +21,8 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 -->
 
-<refentry id="sd_watchdog_enabled">
+<refentry id="sd_watchdog_enabled"
+        xmlns:xi="http://www.w3.org/2001/XInclude">
 
         <refentryinfo>
                 <title>sd_watchdog_enabled</title>
@@ -54,7 +55,7 @@
                         <funcprototype>
                                 <funcdef>int <function>sd_watchdog_enabled</function></funcdef>
                                 <paramdef>int <parameter>unset_environment</parameter></paramdef>
-                                <paramdef>const uint64_t *<parameter>usec</parameter></paramdef>
+                                <paramdef>uint64_t *<parameter>usec</parameter></paramdef>
                         </funcprototype>
                 </funcsynopsis>
         </refsynopsisdiv>
@@ -68,30 +69,37 @@
                 which the manager will act on the service if it did
                 not get such a notification.</para>
 
+                <para>If the <varname>$WATCHDOG_USEC</varname>
+                environment variable is set, and the
+                <varname>$WATCHDOG_PID</varname> variable is unset or
+                set to the PID of the current process, the service
+                manager expects notifications from this process. The
+                manager will usually terminate a service when it does
+                not get a notification message within the specified
+                time after startup and after each previous message. It
+                is recommended that a daemon sends a keep-alive
+                notification message to the service manager every half
+                of the time returned here. Notification messages may
+                be sent with
+                <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+                with a message string of
+                <literal>WATCHDOG=1</literal>.</para>
+
                 <para>If the <parameter>unset_environment</parameter>
                 parameter is non-zero,
                 <function>sd_watchdog_enabled()</function> will unset
                 the <varname>$WATCHDOG_USEC</varname> and
                 <varname>$WATCHDOG_PID</varname> environment variables
-                before returning (regardless of whether the function call
-                itself succeeded or not). Further calls to
-                <function>sd_watchdog_enabled()</function> will then
-                return with zero, but the variable is no longer
-                inherited by child processes.</para>
+                before returning (regardless of whether the function
+                call itself succeeded or not). Those variables are no
+                longer inherited by child processes. Further calls to
+                <function>sd_watchdog_enabled()</function> will also
+                return with zero.</para>
 
                 <para>If the <parameter>usec</parameter> parameter is
                 non-NULL, <function>sd_watchdog_enabled()</function>
-                will return the timeout in µs for the watchdog
-                logic. The service manager will usually terminate a
-                service when it did not get a notification message
-                within the specified time after startup and after each
-                previous message. It is recommended that a daemon
-                sends a keep-alive notification message to the service
-                manager every half of the time returned
-                here. Notification messages may be sent with
-                <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
-                with a message string of
-                <literal>WATCHDOG=1</literal>.</para>
+                will write the timeout in µs for the watchdog
+                logic to it.</para>
 
                 <para>To enable service supervision with the watchdog
                 logic, use <varname>WatchdogSec=</varname> in service
@@ -115,13 +123,7 @@
         <refsect1>
                 <title>Notes</title>
 
-                <para>This function is provided by the reference
-                implementation of APIs for new-style daemons and
-                distributed with the systemd package. The algorithm
-                it implements is simple, and can easily be
-                reimplemented in daemons if it is important to support
-                this interface without using the reference
-                implementation.</para>
+                <xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
 
                 <para>Internally, this functions parses the
                 <varname>$WATCHDOG_PID</varname> and
@@ -131,30 +133,6 @@
                 of the current process, under the assumption that in
                 that case, the variables were set for a different
                 process further up the process tree.</para>
-
-                <para>For details about the algorithm, check the
-                liberally licensed reference implementation sources:
-                <ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/libsystemd-daemon/sd-daemon.c"/>
-                and <ulink
-                url="http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/sd-daemon.h"/></para>
-
-                <para><function>sd_watchdog_enabled()</function> is
-                implemented in the reference implementation's
-                <filename>sd-daemon.c</filename> and
-                <filename>sd-daemon.h</filename> files. These
-                interfaces are available as a shared library, which can
-                be compiled and linked to with the
-                <constant>libsystemd-daemon</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
-                file. Alternatively, applications consuming these APIs
-                may copy the implementation into their source
-                tree. For more details about the reference
-                implementation, see
-                <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
-
-                <para>If the reference implementation is used as
-                drop-in files and -DDISABLE_SYSTEMD is set during
-                compilation, these functions will always return 0 and
-                otherwise become a NOP.</para>
         </refsect1>
 
         <refsect1>
@@ -184,6 +162,19 @@
                 </variablelist>
         </refsect1>
 
+        <refsect1>
+                <title>History</title>
+
+                <para>The watchdog functionality and the
+                <varname>$WATCHDOG_USEC</varname> variable were
+                added in systemd-41.</para>
+
+                <para><function>sd_watchdog_enabled()</function>
+                function was added in systemd-209. Since that version
+                the <varname>$WATCHDOG_PID</varname> variable is also
+                set.</para>
+        </refsect1>
+
         <refsect1>
                 <title>See Also</title>
                 <para>