anyway, here's user-space debugfs
```
$ findmnt /run/febug /run/febug febug fuse.febug rw,nosuid,nodev,relatime,userid=0,groupid=0,defaultpermissions,allowother $ ./out/examples/vector-sort & [1] 1409 $ LDLIBRARYPATH=out ./out/examples/string-qsort & [2] 1410 $ ls /run/febug/ 1409 1410 $ ls -l /run/febug/ dr-xr-x--- 4 nabijaczleweli users 0 Jan 15 19:52 1409 dr-xr-x--- 3 nabijaczleweli users 0 Jan 15 19:52 1410 $ ls /run/febug/1409/ comparisons cooldata $ cat /run/febug/1409/* 24 -3 -2 -3 -2 -3 -2 3 -1 -2 -3 0 1 2 3 -1 -2 -3 0 1 2 3 -1 -2 -3 0 1 2 3 -1 2 1 0 1 2 3 -1 0 -1 0 1 2 3 $ cat /run/febug/1409/* 45 -3 -2 -3 -2 -3 -2 -3 -2 -2 -3 -3 -2 -1 3 -1 1 0 0 1 2 3 2 -1 3 0 1 2 3 -1 2 1 0 1 2 3 -1 0 -1 0 1 2 3 $ grep . /run/febug/*/* /run/febug/1450/comparisons:71 /run/febug/1450/cooldata:-3 -3 -3 -3 -3 -3 -2 -2 -2 -2 -2 -2 -1 3 -1 1 0 0 1 2 3 2 -1 3 0 1 2 3 -1 2 1 0 1 2 3 -1 0 -1 0 1 2 3 /run/febug/1451/cool_data:3012987654ACEFOLJKODNIEMIGHBPPbdWwnfTpXQcreRlVvUSitZQWjRTYUazuqwertyuiopoxyhmYsgkq $ kill %1 $ ls /run/febug/ 1410 ```
[/var]/run/febug.sock by default, with a corresponding mount at [/var]/run/febugfebug_message (variable_id, variable_type, signal, and name (see febug-abi.h)) – name gets a file under the directoryopen() of the file, the client is sent an attn_febug_message (variable_id and variable_type) and the write end of a pipe and (if signal wasn't SIGKILL) notifiedread()s copy directly from the corresponding end of the pipe – the client must close() it by the time it returns from the signal handler (or, if using some other mechanism, when otherwise done representing)stop_febug_message (variable_id) to deregister, disappearing the fileOr, perhaps (server is box, program is oval, user is trapezium):
For a Linux system: 
* install libfuse3-dev, pkg-config, and mandoc
* make
For FreeBSD: 
* install gmake, fusefs-libs3, and pkgconf
* gmake
For NetBSD:
* install lang/clang – the GCC 7.5 shipped with NetBSD 9.1 is too ancient
* gmake CC=clang CXX=clang++ LTO=n
For OpenBSD: 
* install gmake
* gmake CXX=c++ LTO=n
For other platforms: * ports welcome!
To build the Rust crate, its examples, and documentation, install cargo/rust/lang/rust[-bin]/rust and run [g]make rust-build rust-doc,
but that is irrelevant to the casual builder.
dot(1) from graphviz is also needed to regenerate the diagram. though that itself is optional.
When built for Linux, the default socket path is /run/febug.sock, otherwise it's /var/run/febug.sock.
On OpenBSD the processes are authenticated by their effective UID/GID.
For a system-wide instance, run febug /run/febug/ & (or /var/run/febug/, or wherever else, as the case may be) as root.
To run a user-local instance, the fusermount3 helper is required, and export FEBUG_SOCKET=/run/user/$(id -u)/febug.sock
followed by febug /run/user/$(id -u)/febug/ & should work for programs using libfebug and libfebug++;
programs using a different ABI wrapper are encouraged to respect this environment variable as well.
init/ contains systemd units for these two use-cases (though that path has to be set manually in the environment debugged programs' environment),
FreeBSD/NetBSD and OpenBSD rc.d scripts for the global one.
See the files in out/examples/, which both sort with sleeps in comparison functions, for how they operate.
There's the tracker, but also see the list below.
Send a patch inline, as an attachment, or a git link and a ref to pull from to the list (~nabijaczleweli/febug@lists.sr.ht) or me directly. I'm not picky, just please include the repo name in the subject prefix.
Please use the tracker, the list, or Twitter.
To all who support further development on Patreon, in particular: