CI build coverage for examples embedded in documentation is missing about systemd

[yuwata]

I am working on this.

[poettering]

The right fix for this issue is probably not just to fix the example, but to test-build all examples we ship as part of CI

[bluca]

It compiles and runs just fine here on bookworm, which version of gcc did you try it with?

$ gcc man/notify-selfcontained-example.c -o /tmp/notify
$

[evverx]

gcc -std=c99 ./man/notify-selfcontained-example.c

[evverx]

The right fix for this issue is probably not just to fix the example, but to test-build all examples we ship as part of CI

Agreed. As far as I know currently the headers are compiled but I'm not sure what's going on with the examples. To judge from #32030 (comment) at least some examples should be compiled as far as I understand but that's something @mrc0mmand probably knows better.

[yuwata]

BTW, should the test code built with -std=gnu11, which is our default? Or, -std=c99 or something non-gnu standard?

[evverx]

As far as I can see at least the headers are compiled with all sorts of standards

src/systemd/meson.build:        foreach opt : ['-std=c++14',
src/systemd/meson.build:                       '-std=c++17',
src/systemd/meson.build:                       '-std=c++20',
src/systemd/meson.build:                       '-std=c++23',
src/systemd/meson.build:                       '-std=c++26',

because they can be embedded in all sorts of things. The example is supposed to be copy-pastable too so it should probably be compiled with -std=c*. (I just copy-pasted the example to a build system where it failed to compile spectacularly)

[yuwata]

WIP branch -> #32057.

[bluca]

Turns out man/notify-selfcontained-example.c did compile on all tested combinations without changes, hence retitling accordingly

[evverx]

It doesn't. Without -D_GNU_SOURCE it isn't exactly self-contained. That being sad I poked it and it's useless because sd_notify usually comes with sd_listen and it's necessary to look at libsystemd anyway.