From 06b98a56d4422647cffae9b52577cf2ae8aa8991 Mon Sep 17 00:00:00 2001
From: Rainer Gerhards <rgerhards@adiscon.com>
Date: Wed, 25 Nov 2009 15:57:38 +0100
Subject: doc: added info on compile settings for atomic ops when building from
 source

---
 doc/build_from_repo.html | 29 +++++++++++++++++++++++++++--
 doc/manual.html          |  1 +
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/doc/build_from_repo.html b/doc/build_from_repo.html
index 8d3b20fe..a06863e1 100644
--- a/doc/build_from_repo.html
+++ b/doc/build_from_repo.html
@@ -43,12 +43,37 @@ you downloaded an official distribution tarball (see the
 <a href="install.html">rsyslog install guide</a>, starting at step 2,
 for further details about that).
 
+<h2>Special Compile-Time Options</h2>
+<p>On some platforms, compile-time issues occur, like the one shown below:
+<p><pre><code>
+make[2]: Entering directory `/home/az/RSyslog/rsyslog-5.5.0/tools'
+  CCLD   rsyslogd
+rsyslogd-omfile.o: In function `getClockFileAccess':
+/home/az/RSyslog/rsyslog-5.5.0/tools/omfile.c:91: undefined reference to `__sync_fetch_and_add_8'
+/home/az/RSyslog/rsyslog-5.5.0/tools/omfile.c:91: undefined reference to `__sync_fetch_and_add_8'
+/home/az/RSyslog/rsyslog-5.5.0/tools/omfile.c:91: undefined reference to `__sync_fetch_and_add_8'
+</code></pre>
+<p>Note that the exact error messages can be different. These type of errors stem down to
+atomic instruction support in GCC, which is somewhat depending on the machine architecture it
+compiles code for. Very old machines (like the original i386) do not even at all provide support
+for these instructions.
+<p>The availability of atomic instructions is vital for rsyslog - it can not be built without them.
+Consequently, there is a configure check included for them. But under some circumstances,
+GCC seems to report they are available, but does not provide implementations for
+all of them (at least this is my observation...). The simple cure is to make sure that
+GCC generates code for a modern-enough architecture. This, for example, can be done as
+follows:
+<p><pre><code>
+./configure CFLAGS="-march=i586 -mcpu=i686" --enable-imfile ... (whatever you need)
+</code></pre>
+<p>These settings should resolve the issue .
+
 <p>[<a href="manual.html">manual index</a>]
 [<a href="http://www.rsyslog.com/">rsyslog site</a>]</p>
 <p><font size="2">This documentation is part of the
 <a href="http://www.rsyslog.com/">rsyslog</a> project.<br>
-Copyright &copy; 2008 by <a href="http://www.gerhards.net/rainer">Rainer Gerhards</a> and
+Copyright &copy; 2008, 2009 by <a href="http://www.gerhards.net/rainer">Rainer Gerhards</a> and
 <a href="http://www.adiscon.com/">Adiscon</a>. Released under the GNU GPL 
-version 1.2 or higher.</font></p>
+version 3 or higher.</font></p>
 </body>
 </html>
diff --git a/doc/manual.html b/doc/manual.html
index 480bf56c..c672af58 100644
--- a/doc/manual.html
+++ b/doc/manual.html
@@ -69,6 +69,7 @@ syslog sender over NAT</a> (online only)</li>
 <li><a href="debug.html">debug support in rsyslog</a></li>
 <li>Developer Documentation
   <ul>
+  <li><a href="build_from_repo.html">building rsyslog from the source repository</a></li>
   <li><a href="dev_oplugins.html">writing rsyslog output plugins</a></li>
   <li><a href="dev_queue.html">the rsyslog message queue object (developer's view)</a></li>
   </ul></li>
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