Hot Code Reloading in C

[@dancinglazer1628]

I loved when zozi said it’s zozin time and zozied all over

[@distant6606]

🤣

[@maxmster55]

My favorite part

[@waxlbloh6450]

😳

[@adr420]

❤

[@tekno679]

I once attempted to write a music visualizer in python and failed horribly. This man did it in C and made it hot-swappable. Respect.

[@contentprogramming]

try it again to prove to yourself that youre improving ;)

[@tekno679]

@@contentprogramming Sadly I don't think I'll have time for that, but I think I did improve, because now I'm doing an image->sound conversion program for my bachelor's thesis 😎

[@sinewaveaddict]

@@tekno679Making some sound out of a FFT transformation of the discrete information present in the image, I presume? It sounds like an interesting project!

[@tekno679]

@@sinewaveaddict I'm planning on it being a modular program where you can select the exact algorithm you want to use for the conversion. Currently I have an algorithm that does straightening of the image by a space-filling curve and mapping to frequencies and some other basic ones. I did think about adding a DCT too, but the most challenging thing about this is that it increases the space to 3D essentially and you want to output a "1D" sound that somehow corresponds to the input.

[@vitfirringur]

In my late teens I wrote an irc bot in C which used hot reloading to support plugins. I did this by parsing the the shared objects manually and looking for exported functions that were prefixed by IRC commands and an underscore: PRIVMSG_foo, etc. Probably the coolest, most advanced thing I had built at that point. This sort of reminds me of that.

[@RobertFletcherOBE]

No lies from the artists, Once you get good at drawing you don't need smoothing (though they do still use it when they don't need control). The reason your line is jittery is your drawing from your wrist, and your drawing short strokes, digital artists zoom in so that they can do long fluent strokes from the elbow and shoulder (broader radius). (source: classically trained animator who now develops tools for creatives). Also I hope it goes without saying. Awesome stream :)

[@TsodingDaily]

Oh! I see what you mean! Thanks! I'll practice that.

[@DominicShillingford]

The math as to which frequencies you get from the FFT is a bit more complicated than you used here. There are two issues, because of reasons the top half of your FFT (for example elements 128-255 if N = 256) will mirror the bottom half and doesn't give you any more information, you might as well throw it away. The highest frequency you get will always be half of the sampling frequency (for example 22.05 kHz if you use 44.1 kHz audio). You can't change this even by increasing N and it will be the middle (emph. middle) element of your FFT vector. Your value of N will determine the lowest frequency you can resolve, it will be 44.1 kHz (again assuming 44.1 kHz audio) divided by the number of samples. Say you choose N = 2048 then the FFT[0] will be your zero hertz amplitude then FFT[1] will be 44.1 kHz / 2048 = 21.53 Hz and FFT[2] will be 43.06 Hz. This will continue until FFT[1024] which will give the amplitude at half the sampling rate, i.e. 22.05 kHz. You can throw away everything after this because it will just mirror the first half (blame Nyquist). Also it's customary to view both the amplitude and the frequency logarithmically in which case your amplitude is essentially in dB (human's also perceive amplitude logarithmically). Also you'll want to sum over the bins if you view the frequencies logarithmically instead of average.

[@pagenotfound_code_404]

yepieee!!! Thats the think I'm interested rn, interactive programming, jit compilers, hot reloading, things like that. this video is just in time!!!

[@zombozer6333]

For the macro around 2:04:44 you can use the # symbol to turn symbols like 'plug_hello' into strings. #define PLUG_HOOK(f_name, libplug) \ do { \ f_name = dlsym(libplug, #f_name); \ if (f_name== NULL) { \ fprint(stderr, "ERROR: could not find %s symbol in %s: %s", \ #f_name, libplug_file_name, dlerror()); \ return false; \ } \ while(1) \ You could use it like this: PLUG_HOOK(plug_hello, libplug); I haven't tested this though. You still need to declare all the global variables and repeat this macro for every function but it's a pretty simple solution for what it does.

[@mohammedalhaddar2182]

Why is it enclosed in an infinite loop?

[@IGrizzllyGuy]

@@mohammedalhaddar2182 I think he wanted to say while(0);

[@JonnyDeRico]

you could use a sine wave sweep to check for correct working fft

[@flyLeonardofly]

1:26:58 Dap, dap technology from the 70ies😂😂😂😂

[@zombozer6333]

Padding samples with zeros caused smoothing around 1:38:12 also the range of frequencies you get from the fft depends only on the sample rate not the number of samples. The number of samples only effects the precision of the frequencies you get back.

[@steled03]

Its always possible to implement a raylib callback handler inside the program, which calls the callback in the plu gin with some data argument!

[@robsokolowski9015]

Flyway reminds me a bit of Lamdera, a "full stack Elm" that has type safe migrations for the stateful backend.

[@ryonagana]

this was perfectly done by Id Software,, used in Quake 2 Engine, when you enter in a server it hot loads the server dynamic library of the game, doesnt matter if the server is running on windows or linux, it just take cares of the loading and endianess

[@francklenormand2680]

The technic to clean all the symbols resolution is to resolve only 1: a structure containing all the pointers on functions. The struct must be defined in the plugin and retrieved by main app

[@zombozer6333]

The high frequencies seem to be shown to be very low. Maybe you could sum them instead of taking the average. That would also make more sence to me because it preserves the area under the curve (sort of like the energy in the sound).

[@ferasboulala6220]

This is exactly what should have been done with a log scale on top for visualization, if needed.

[@parallel4344]

I have also done something like this for my visualizers.

[@TECHN01200]

I love the message of programming is universal. I am entirely with you on this point, it disappoints me that there are hardly any low level jobs anymore for anyone with fewer than 5 years of C experience.

[@kibels894]

If you're skilled enough in C to work in low level then put it on your resume. If you have the skills there's no reason to let your resume be the reason they reject you.

[@brd5548]

Very entertaining and educational demonstration! Python dev here😝, but we do have dll hot reloading functionality within python since very early days. For dlopen/dlclose/dlsym calls, they exist under the standard lib ctypes, whose signatures are pretty much the same with the posix ones if I remember. The whole CPython interpreter itself is just basically a huge C virtual machine, so it's pretty easy for cpython to interop with c code. For JavaScript, I do believe the node.js runtime has similar functionalities, but I'm not sure if it's a js language standard feature or just a node.js thing.

[@DanelonNicolas]

I love this man... ❤ the moment when hot realoading works was EPIC!!!! how about that!!!

[@enc6428]

js hot reloading is just reading a js file as a string and passing it to eval()

[@awesomeguy11000]

If I could make a stream request: try to program anything without warnings using clang -Weverything and clang static analyzer

[@arcxm]

23:13 "reload this hot library" ^^, 1:26:56 xD

[@TankorSmash]

1:27:00 Python does have hotreloading, basically built in. Javascript absolutely has hot reloading if you use a build tool. It absolutely wasn't your point but in case anyone is curious, it's very common!

[@haakonness]

In the start of the stream he said that it is possible in python, js and even java. So he is aware, he was just hyping :P

[@antropod]

I wonder if Twitch stores subscription money as a complex number in their database

[@byterbrodTV]

Thank you for video. Interesting project. I guess after watching this video we all doesn't need java or c# with their "VM hotswap thingy" anymore. Will put my little thoughts below. 1:03:00 - I suppose guy from chat means the case when you press R and hold it. I wonder, will it reload plugin every frame? I don't know how exactly KeyPressed() works, but in that cases something like KeyReleased() might be better, because it would called once when you release your R button. 1:35:47 - As a little bit of music making person i would say that normal people can't hear frequences after about 15-16k, it's just a high pitch noise, so 2^14 is enough for EQ. Keep this project up, we waiting for the moment when we could drag and drop music into player by hand :>

[@bobby9568]

The King is back! 🎉

[@mightyhelper8336]

Maybe you could run some pure sine waves to test it

[@gwentarinokripperinolkjdsf683]

I am about to start working on hot reloading on a simple OS I am working on (it's not really an OS, just a un hosted application) for quite similar reasons, I find debugging on real hardware (and it has to be on real hardware) to be very painful, my idea is to have the kernel listen on the serial port (which surprisingly modern computers have) and listen for commands, one of which would take a binary blob as a parameter that would contain a recompiled version of the OS which it would then overwrite

[@SimGunther]

Virgin VM image vs Chad hot reloaded .so file 😎

[@nilsnilss]

you can use multiple compilation buffers by renaming the compilation buffer and then switiching the buffer and then start a new compilation

[@flleaf]

1:12:18 two weeks? isn't there only one video on youtube on this?

[@OxAA00]

Great channel and great video!

[@portersky]

Bro just made ringbuffer like I did in my DSP lab 😂

[@Celicaw8]

1:06:39 Couldn't you make a wrapper function with the same signature, where the bufferData is a structure with the bufferdata and the userdata, then pass this wrapper to the function you registered the callback with?

[@l.f-z9i]

Respect and thanks the remarkable work.

[@maximeetienne2601]

Great video, very informative. Could someone explain why did he was forced to link dynamically raylib to make the hot reloading work ?

[@gameofpj3286]

Maybe smooth the fft by using 50% of the previous fft and 50% of the new calculated one :D I think it's called exponential smoothing or something like that.

[@jamesbarret4240]

afaik it's called temporal smoothing, similar algorithms are used in anti-aliasing (TAA). good idea

[@gameofpj3286]

@@jamesbarret4240 Yea it's exponential smoothing. Probably a good idea to have it just smoothed when it goes down tho.

[@HimanshuSharma-b3q3u]

Question: does 2.5Ghz wifi use fft at endpoints (aka the devices) or they use tuned antenna for it. please some one please tell me.

[@ShowierData9978]

you can use a callback within the main program; then call the dll callback

[@bloomingvision]

Thats the point of all this though - its about not doing the short cuts. "just use a this and this is all unnecessary" . T's "Programming is Universal" speech captures the essence of it. There is a fundamental universality that we should know. LINKERS AND LOADERS - A beautiful are. We should all know it. My Book coming out: Computer Science in Rust :) Will re-deliver these arts. Soding.... this goes down in my book as the Traders equivalent of Gecko's Greed is Good speech -- PROGRAMMING IS UNIVERSAL.

[@postmodernist1848]

The standard library has an M_PI #define. GNU extension has M_PIf. Also why not just cast M_PI to float?

[@dancinglazer1628]

apparently M_PI is non standard

[@eazypeazy8559]

so fcking cool. I watch your streams as entertainment random CS course....

[@not_just_burnt]

i love myself some fearofdark music too!!

[@phill13able]

How to confirm neovim like yours?

[@johnhammer8668]

How did you find static linking was the cause for crash? Why does dynamically linked library does not crash?

[@Shonicheck]

12:57 The --cake-- smooth line is a lie!

[@SimonBuchanNz]

One really annoying thing with trying to do this especially in other languages is if you use global init code or thread locals or the like, it just stops working because apparently that's just too hard for glibc to figure out. Ugh. A more reliable and buzzword friendly approach is to use WASM, but now you have the mess of interop.

[@exciting-burp]

Hot teloading is a big deal in JS bevause everything is unnecessarily complicated in JS.

[@rakaboy1619]

its like i cant build a http server and this man out here casually makes a hot code reloading in C in a time it takes me to make a class. trutly a tsoding moment

[@wrnlb666]

libdl has a windows wrapper. I think it is crossplatform enough?

[@gaweqqwgfas9980]

you're doing cool stuff while i struggle to install a c compiler ffs

[@TsodingDaily]

You can do it! I believe in you!

[@aciddev_]

zozi bought new camera! yay

[@vividimagination2044]

If you want to get around these annoying "accept our cookies or else" prompts without accepting anything then you can just open your browsers console, find the modal and elegantly slam that delete button with fervor

[@lazarstanojevic7841]

is there a video where he talks about his setup (editor, os and stuff like that)?

[@Stroopwafe1]

Editor: Emacs OS: Debian Keyboard: Yes /j He has some videos where he talks about that it doesn't matter what he uses, just use what works best for you

[@Gigasharik5]

Tsoding, was you ever try to write AGI?

[@slendi9623]

This is really cool, I tried doing the same thing but with getting the .so file's mtime and doing a compare on that `if (get_modification_date() > prev_modification_date)`, however it likes to bus error and segfault for some reason. But when I do IsKeyPressed, it just werks. Weird.

[@slendi9623]

Its because I recompiled main

[@andrewlamichhane1090]

Is that a new zozing place ?

[@paco3447]

Regarding this, a whatever’s Erlang project could be a next and funny try.

[@deathvall3y]

0:03:0 why does it say porn folder 7.6 GiB in the tray 🤔

[@rogerbusquetsduran5596]

How were you anble to build the shared lib while having it opened by your application?

[@SoftBreadSoft]

readonly does not lock files, so read+write succeeds.

[@filipbook5605]

Does anyone here have a license for a switch case developer??? I'm looking for one

[@mason-pe5lk]

Sounds complicated. I would've just piped the music to my headset and to the visualizer.

[@RagePower2000]

What font do you use?

[@somecretin]

the pervasive self-absorbed narcissism is such a turn-off

[@zombozer6333]

I think it's crashing because you are passing a callback to instruction in the SO. Then when the SO is closed the callback is called and it segfaults. I gues when the code barely changed the new version gets loaded into the same memory? That seems weird though because I would expect the memory layout to be randomized through ASLR although I'm not an expert on that. To fix this you could place the callback function in the static file. This can then call into the updated version of the SO. Otherwise you would have to somehow pause the audio so the callback doesn't get called. (Edit): I didn't see the extra section at the end. You already solved it so nvm.

[@user-oe4id9eu4v]

ASLR is something to do with kernel loading process into memory with exec* syscalls. Dynamic linking using dl* functions is resolved by dynamic linker, which is part of libc. So address of each functions will change every time program is reloaded, but not when simply shared object is reloaded.

[@fish1r1]

dll is dynamic link library.

[@bibliusz777]

What is wrong with Nix?

[@Narblo]

why dont you use pragma once?

[@aviationbutterr]

pragma once is a non-standard directive. header guards will always work on any standard-compliant compiler

[@png261]

what software does he use to zoom in out and dim screen ?

[@flleaf]

boomer (on his github)

[@png261]

​@@flleaf thanks a lot, such a useful tool

[@gameofpj3286]

Also I really love how you can see the melody playing at 2:13:07 :o

[@万宇阳]

"Can your python and javascript do that??!" Python and javascript don't segfault lol

[@ryonagana]

imp library, now importlib in Python 3

[@Isaac-zy5do]

Just give you NaNs instead lol

[@tauraamui]

you should use Excalidraw instead of trying to handwrite text with a mouse.

[@begga9682]

1:26:58 Python goobers got owned lmao

[@LogicEu]

Very cool stuff

[@desertfish74]

Rezozing ze code

[@Gordonfreems]

This was a vibe, amazing stream

[@glorioussir9673]

You can use "x macro" for function loading deduplication, quite handy technic en.wikipedia.org/wiki/X_macro

[@bd3670]

Am I the only one who noticed: "Porn Folder" in his terminal?

[@heyyouhere]

todays session is hot omgggg

[@parlor3115]

Oh yeah!

[@titaniumtomato7247]

So is this how a shell is made, or does the shell just have its own interpreter?

[@bonniesimon14]

Love the video without it, but still would be awesome to have timestamps.

[@varshneydevansh]

Woah in just 2 mins

[@dryoldcrabman6890]

1:11:46 kek

[@azir8930]

❤

[@sinamobasheri]

This is not hot I wanna hot

[@monprenometmonnom5518]

en.wikipedia.org/wiki/Tiny_C_Compiler : TinyC Compiler able to compile C string code inside EXE

[@flleaf]

interesting, didn't know youtube doesn't delete comments with wikipedia links

[@enclave2k1]

if code_is_working { self.is_twerking = true; }

[@MrDujmanu]

What font(s) do you use?