X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsd-login.xml;h=3fc0e16f698c7a177da7e2544445ad20cbb15fbf;hp=9926d2b85cfd85df91bebb2384d233754fc6c8da;hb=5079a105e701f17439635e76d8cb3052badbb34c;hpb=595aae376fae21f885ec9af2cac1aaf3ff3e9bee 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