The annotation applies to the method as a whole, not to individual arguments, so the existing annotations don't have any effect. This was hidden by gdbus-codegen's automatic handling of arguments of type 'h', but that change was reverted, resulting in a broken build.
Sysprof is a sampling profiler that uses a kernel module to generate stacktraces which are then interpreted by the userspace program "sysprof".
See the Sysprof homepage for more information.
Questions, patches and bug reports should be sent to the sysprof mailing list sysprof-list@gnome.org.
The list is archived in https://mail.gnome.org/archives/sysprof-list/.
Debugging symbols
The programs and libraries you want to profile should be compiled
with -fno-omit-frame-pointer and have debugging symbols available,
or you won't get much usable information.
Building Sysprof
You need some packages installed. The package names may vary depending on your distribution, the following command works on Fedora 25:
sudo dnf install gcc gcc-c++ ninja-build gtk3-devel
Then do the following:
meson --prefix=/usr build
cd build
ninja
sudo ninja install
WARNING: ninja install will mostly install under the configured install
prefix but installs systemd service configuration directly in the system
default location /usr/lib/systemd so it won't work without root privileges,
even if the install prefix is a user-owned directory.