A lot of the comments are actually wrong though. For example, someone accused the author of lying for saying "There is no documented, stable way for a daemon to use either of these options without linking to D-Bus's library and/or systemd's library" - and as evidence, pointed to systemd's "stable interface" for startup notification, which is a C API that requires daemons to link against a systemd-provided library. Their own source confirms the blog poster's claims, and yet they accuse him of lying and having no scruples whatsoever for making them.
Edit: Interestingly, it looks like one of the other Wiki pages[1] does specificially call out the underlying $NOTIFY_SOCKET protocol as a stable interface. (Then points to an authoritive chart that doesn't, presumably because the implementation details of the other sd-daemon.h APIs aren't stable despite being documented in the same way?)
The code for that is stable, it is just that the recommended way is using that library. When people asked, the code was provided to do this without linking. Just that linking is way more reliable.
The comment should've stated something like "the way to do this is not documented". The way it is currently worded implies something totally different.
I'm saying that linking to a function is more reliable than copy/pasting that stuff into your program. If you want to argue that copy/pasting is totally fine, go ahead. I'm sure enough people will respond to that :-P
Edit: Interestingly, it looks like one of the other Wiki pages[1] does specificially call out the underlying $NOTIFY_SOCKET protocol as a stable interface. (Then points to an authoritive chart that doesn't, presumably because the implementation details of the other sd-daemon.h APIs aren't stable despite being documented in the same way?)
[1] http://www.freedesktop.org/wiki/Software/systemd/InterfaceSt...