From 5079a105e701f17439635e76d8cb3052badbb34c Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 19 Dec 2011 17:40:31 +0100 Subject: [PATCH 1/1] man: extend sd-login(7) in regards to mixing D-Bus and synchronous library calls a bit --- man/sd-login.xml | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/man/sd-login.xml b/man/sd-login.xml index 9926d2b85..3fc0e16f6 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. - These functions access data in + These functions synchronously access data in /proc, /sys/fs/cgroup and /run. All of these are virtual file systems, hence the runtime cost of the accesses is relatively cheap. + It is possible (and often a very good choice) to + mix calls to the synchronous interface of + sd-login.h 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 + sd-login.h interfaces such as the + login monitor are asynchronous and not ordered against + each other. + If the functions return string arrays, these are generally NULL terminated and need to be freed by the caller with the libc -- 2.30.2