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-rw-r--r--man/sd-login.xml12
1 files changed, 11 insertions, 1 deletions
diff --git a/man/sd-login.xml b/man/sd-login.xml
index 9926d2b85c..3fc0e16f69 100644
--- a/man/sd-login.xml
+++ b/man/sd-login.xml
@@ -77,13 +77,23 @@
you need to utilize the D-Bus API of
systemd-logind, instead.</para>
- <para>These functions access data in
+ <para>These functions synchronously access data in
<filename>/proc</filename>,
<filename>/sys/fs/cgroup</filename> and
<filename>/run</filename>. All of these are virtual
file systems, hence the runtime cost of the accesses
is relatively cheap.</para>
+ <para>It is possible (and often a very good choice) to
+ mix calls to the synchronous interface of
+ <filename>sd-login.h</filename> with the asynchronous
+ D-Bus interface of systemd-logind. However, if this is
+ done you need to think a bit about possible races
+ since the stream of events from D-Bus and from
+ <filename>sd-login.h</filename> interfaces such as the
+ login monitor are asynchronous and not ordered against
+ each other.</para>
+
<para>If the functions return string arrays, these are
generally NULL terminated and need to be freed by the
caller with the libc