check for _POSIX_C_SOURCE instead of __USE_POSIX*

[elogind.git] / README

diff --git a/README b/README
index e08b1ddd0a74a313e9f7ba6dfd1e20b85d09c745..0cd868ade28b70e40163bbb3ddfca44f0e536b8c 100644 (file)
--- a/README
+++ b/README
@@ -102,7 +102,7 @@ Elogind does not manage virtual terminals.
 
 Elogind does monitor power button and the lid switch, like systemd,
 but instead of doing RPC to systemd to suspend, poweroff, or restart
 
 Elogind does monitor power button and the lid switch, like systemd,
 but instead of doing RPC to systemd to suspend, poweroff, or restart

-the machine, elogind just does this directly.  For suspend, hybernate,
+the machine, elogind just does this directly.  For suspend, hibernate,

 and hybrid-sleep, elogind uses the same code as systemd-sleep.
 Instead of using a separate sleep.conf file to configure the sleep
 behavior, this is included in the [Sleep] section of
 and hybrid-sleep, elogind uses the same code as systemd-sleep.
 Instead of using a separate sleep.conf file to configure the sleep
 behavior, this is included in the [Sleep] section of


@@ -116,6 +116,32 @@ flag.
 
 The PAM module is called pam_elogind.so, not pam_systemd.so.
 
 
 The PAM module is called pam_elogind.so, not pam_systemd.so.
 

+Elogind and the running cgroup controller
+-----------------------------------------
+While 'configure' runs, it will detect which controller is in place.
+If no controller is in place, configure will determine, that elogind
+should be its own controller, which will be a very limited one.
+
+This approach should generally work, but if you just have no cgroup
+controller in place, yet, or if you are currently switching to
+another one, this approach will fail.
+
+In this case you can do one of the two following things:
+
+ 1) Boot your system with the target init system and cgroup
+    controller, before configuring and building elogind, or
+ 2) Use the --with-cgroup-controller=name option.
+
+Example: If you plan to use openrc, but openrc has not yet booted
+         the machine, you can use
+         --with-cgroup-controller=openrc
+         to let elogind know that openrc will be the controller
+         in charge.
+
+However, if you set the controller at configure time to something
+different than what is in place, elogind will not start until that
+controller is actively used as the primary controller.
+

 License
 -------
 
 License
 -------