From e6ea3b07e25b09481b010558f8bfdfb57dcbb85e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Mon, 15 Oct 2012 16:22:47 +0200
Subject: doc: Document ERL_CRASH_DUMP_SECONDS behaviour

* heart reboot behaviour
* erl_crash.dump file write behaviour
---
 lib/kernel/doc/src/heart.xml | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'lib/kernel/doc/src/heart.xml')

diff --git a/lib/kernel/doc/src/heart.xml b/lib/kernel/doc/src/heart.xml
index 26d1e27822..2826d3d00a 100644
--- a/lib/kernel/doc/src/heart.xml
+++ b/lib/kernel/doc/src/heart.xml
@@ -71,6 +71,39 @@
       timeout and try to reboot the system. This can happen, for
       example, if the system clock is adjusted automatically by use of
       NTP (Network Time Protocol).</p>
+
+  <p> If a crash occurs, an <c><![CDATA[erl_crash.dump]]></c> will <em>not</em> be written
+	  unless the environment variable <c><![CDATA[ERL_CRASH_DUMP_SECONDS]]></c> is set.
+  </p>
+
+    <pre>
+% <input>erl -heart -env ERL_CRASH_DUMP_SECONDS 10 ...</input></pre>
+  <p>
+	  Furthermore, <c><![CDATA[ERL_CRASH_DUMP_SECONDS]]></c> has the following behaviour on
+	  <c>heart</c>:
+  </p>
+  <taglist>
+	  <tag><c><![CDATA[ERL_CRASH_DUMP_SECONDS=0]]></c></tag>
+	  <item><p>
+			  Suppresses the writing a crash dump file entirely,
+			  thus rebooting the runtime system immediately.
+			  This is the same as not setting the environment variable.
+		  </p>
+	  </item>
+	  <tag><c><![CDATA[ERL_CRASH_DUMP_SECONDS=-1]]></c></tag>
+	  <item><p> Setting the environment variable to a negative value will not reboot
+			  the runtime system until the crash dump file has been completly written.
+		  </p>
+	  </item>
+	  <tag><c><![CDATA[ERL_CRASH_DUMP_SECONDS=S]]></c></tag>
+	  <item><p>
+			  Heart will wait for <c>S</c> seconds to let the crash dump file be written.
+			  After <c>S</c> seconds <c>heart</c> will reboot the runtime system regardless of
+			  the crash dump file has been written or not.
+		  </p>
+	  </item>
+  </taglist>
+
     <p>In the following descriptions, all function fails with reason
       <c>badarg</c> if <c>heart</c> is not started.</p>
   </description>
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