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| -rw-r--r-- | man/sd-login.xml | 12 |
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 |