dns plugin: Added support for the old bind-interface.

[collectd.git] / README

diff --git a/README b/README
index 555af86..b639095 100644 (file)
--- a/README
+++ b/README
@@ -112,6 +112,9 @@ Features
       write your own plugins in Perl and return arbitary values using this
       API. See collectd-perl(5).
 
+      This plugin is still considered to be experimental and subject to change
+      between minor releases.
+
     - ping
       Network latency: Time to reach the default gateway or another given
       host.
@@ -250,7 +253,7 @@ Prerequisites
 
   * librrd (optional; headers and library; rrdtool 1.0 and 1.2 both work fine)
     If built without `librrd' the resulting binary will be `client only', i.e.
-    will send it's values via multicast and not create any RRD files itself.
+    will send its values via multicast and not create any RRD files itself.
     Alternatively you can chose to write CSV-files (Comma Seperated Values)
     instead.
 
@@ -272,6 +275,26 @@ Prerequisites
     For compiling on Darwin in general and the `apple_sensors' plugin in
     particular.
 
+
+Crosscompiling
+--------------
+
+    To compile correctly collectd needs to be able to initialize static
+    variables to NAN (Not A Number). Some C libraries, especially the GNU
+    libc, have a problem with that.
+
+    Luckily, with GCC it's possible to work around that problem: One can define
+    NAN as being (0.0 / 0.0) and `isnan' as `f != f'. However, to test this
+    ``implementation'' the configure script needs to compile and run a short
+    test program. Obviously running a test program when doing a cross-
+    compilation is, well, challenging.
+
+    If you run into this problem, you can use the `--with-nan-emulation'
+    configure option to force the use of this implementation. We can't promise
+    that the compiled binary actually behaves as it should, but since NANs
+    are likely never passed to the libm you have a good chance to be lucky.
+
+
 Author
 ------