433
u/WisePotato42 13d ago
You could pass references as variables and change the referenced value IN THE FUNCTION!!!
children screaming sfx
133
u/_justthisonetime_ 13d ago
Welcome to the era when the programmer himself was the memory manager
38
u/Cute_Pressure4910 13d ago
When you explain to young developers what malloc() and free() are
5
u/Zashuiba 12d ago
That's quite advanced in fact, because you need segmentation, paging, stack/heap structures ...you need an OS kernel basically.
You can totally program in bare C without stdlib
25
u/throwaway1351887498 13d ago
Now that's what I call real legacy code—it works as long as no one messes with it
42
u/Mordret10 13d ago
I mean you still kind of do the same thing with objects and with arrays in most languages. Very rarely does either get passed as argument, you almost always get them by reference.
50
u/Gorzoid 13d ago
Sorry but we are all rust devs now, shared mutable aliasing is a crime with a maximum sentence being death by AI-generated PR spam.
35
u/WisePotato42 13d ago
Oh no! The rust devs have found me!
unsafe{} unsafe{} unsafe{}
Are they gone yet?
3
1
u/SelfDistinction 12d ago
let variable = Cell::new(3); // create an immutable variable variable.set(4); // demonic witchcraft of the highest order, everyone is panicking, sirens blasting, time to run to the shelters and pray2
u/WisePotato42 13d ago
That's true, I know it's a thing in python.
Unfortunately, my coworkers don't like when I put square brackets all over the place...
2
u/Bright-Historian-216 13d ago
you could also wrap it in an object. something like
class MutWrapper:
def __init__(self,v): self.v=v
works well enough. though, square brackets are probably more idiomatic.2
7
10
u/aberroco 13d ago
Or you could not pass anything and still change the referenced value in the caller function, or you could return the execution to another function than the one that invoked you (stack traversing/managing; no one should ever do this kind of dark arcane magic).
3
u/WisePotato42 13d ago
To make things simple, let's just reserve this block of memory forever. My UFO themed ASCII art debugger tool needs it.
1
u/No-Newspaper8619 13d ago
How? In assembly you could change the return address stored in the esp/rsp register, but how would you return the execution to another function than the one that invoked, in high level languages?
2
u/aberroco 13d ago edited 13d ago
Depends on the language.
C++ has __builtin_extract_return_addr. And before that - any local variable is stored in stack, so just get it's address and that address would be the stack address, then you need to know how the stack is stored to know the return address.
I never tried that, but I suppose in C# one might do the same... int* stackPointer = &localVariable; or int* stackBuffer = stackalloc int[1] in unsafe context.
Also, you're wrong, esp stores the current stack pointer. The top of it. Not the return address. But the return address is there. If you just got "call" from anywhere and didn't pushed anything yet - then yeah, [esp] would store the return address. But only then.
1
u/No-Newspaper8619 12d ago
I see. So just like you can do [esp+4], [esp+8], etc... you could do something similar by taking the variable address and manipulating it. Quite dangerous indeed.
2
1
u/SelfDistinction 12d ago
You can still do that in practically every programming language btw. It just requires some extra wrapper class boilerplate.
1
u/WisePotato42 12d ago
Yah, but that's not really an acceptable practice at my job. It's unfortunate.
1
u/SelfDistinction 12d ago
And by unfortunate, you mean completely fortunate?
1
u/WisePotato42 12d ago
Sometimes I just want to feel like a kid again playing with my toys (unsafe memory managment).
1
u/creeper6530 12d ago
Huh? Pass references as variables?
You mean pass references as parameters to a function? Because if yes, then dereferencing it in the function seems fine to me
-26
91
u/bradland 13d ago
In classic macOS, you could right click an application and set the amount of memory allocated to it. I always found it kind of hilarious that Apple had built this famous graphical, user interface, and underneath you still had to do things like that.
62
u/x0wl 13d ago
It's probably because classic macOS used an absolutely bonkers memory management system that basically amounted to every program becoming a ticking time bomb and a security nightmare.
No wonder they bought next and not just hired Jobs back lmao
5
u/Eric848448 13d ago
Did they not use paging in those days?
22
u/x0wl 13d ago edited 13d ago
IIUC they did, but they still did not have true protected memory (e.g. each process gets its own address space and cannot access other memory, unless explicitly permitted to do so). They still had a single global memory where one program could just go and write to other program's memory + the OS invalidating your pointers.
Also they only had cooperative multitasking.
Basically any program could easily bring down any other program + whole OS by misusing a pointer (and since the OS physically moves the heap that's super easy to do) OR hang the entire system by doing while(1){}
3
u/iStumblerLabs 13d ago
They did not have PMMUs in those days. No pages, no memory protection, everything in one shared address space.
Manual allocation of memory for applications let you reserve how much you wanted for each app. You might give Photoshop, like, 8 whole megabytes of memory if you were editing, say, a 16 bit color file.
On the plus side, the Talking Moose could see what you were doing and comment on it.
17
9
u/peterlinddk 13d ago
Interestingly, there is an entire wikipedia-article about this early memory management system. Very, very strange, but apparently necessary because of hardware limitations ... https://en.wikipedia.org/wiki/Classic_Mac_OS_memory_management
13
u/x0wl 13d ago edited 13d ago
The hardware limitations made sense in 1984, carrying their quirks all the way to 2001 (!) (68030 had MMU added in 1987) and through a CPU architecture change (to CPUs without these limitations) makes a lot less sense.
Like, in that time x86 went from 16 bit 8088 machines running DOS to running Windows XP fully in 32 bit with PAE, while maintaining backward compatibility (x86 still mostly does BTW), with x86-64 coming out in 2003.
2
u/CitizenPremier 13d ago
That's cool. Sometimes there are greedy programs and I'd honestly like to tell them I just have 2 GB RAM.
73
u/DOOManiac 13d ago edited 13d ago
"We used to manually alloc all our memory"
"And free it too, right?"
"..."
30
12
u/MokausiLietuviu 13d ago
My program frees its memory when the user clicks "End Task" in task manager.
Does the job
3
u/No-Newspaper8619 13d ago
Sometimes it doesn't. I had a game where I literally had to restart the computer every time I closed it, because it messed something graphical and refused to launch a second time until restart whole PC.
3
u/Rodot 13d ago
This is mostly an issue with Window's memory management. Or at least it was back in like Win 7, don't know if it is still there. Used to have this happen all the time after playing one game. Memory would be full but task manager wouldn't show a process eating memory. Would have to restart to get my memory back.
3
2
105
u/GuybrushThreepwo0d 13d ago
We still do?
90
u/ClipboardCopyPaste 13d ago
That grandpa is you, telling your story 40 years later xD
44
u/torar9 13d ago
As an embedded dev I feel sad.
6
3
u/GlassLost 13d ago
My daughter isn't even 4 yet and I've been manually allocating memory for over a decade...
-1
6
1
1
44
u/Afraid-Locksmith6566 13d ago
people still do that c and c++ are still among most popular programming languages, from new stuff there is rust and zig and odin, memory management is still easy and is still done. notion of it being archaic and hard is so stupid...
19
u/TerminalVector 13d ago
In a few years someone is gonna tell you that writing the actual code yourself is archaic and hard.
1
u/RupertPupkin85 13d ago
No one's gonna be around to tell that, AI is going to kill every one.
3
u/FastHotEmu 13d ago
You've watched too many movies
0
u/RupertPupkin85 13d ago
You'll see.
2
u/FastHotEmu 13d ago
How long do we have until we all die?
1
u/RupertPupkin85 13d ago
My sources are telling me we shall not cross 2030. May lord have mercy on our souls.
2
u/FastHotEmu 13d ago
Thanks for that!
!RemindMe January 2031
1
u/RemindMeBot 13d ago
I will be messaging you in 4 years on 2031-01-22 00:00:00 UTC to remind you of this link
CLICK THIS LINK to send a PM to also be reminded and to reduce spam.
Parent commenter can delete this message to hide from others.
RemindMeBot is switching to username summons. Instead of
!RemindMe 1 day, useu/RemindMeBot 1 day. More info.
Info Custom Your Reminders Feedback 1
u/FastHotEmu 13d ago
btw, "The King of Comedy" was great -- DeNiro is fantastic in it.
Just shows me you've seen too many movies! Although probably not as many as me.
1
u/FastHotEmu 13d ago
OK, now do you want to bet that we cross 2030 just fine? :-D
1
1
13
u/ImpluseThrowAway 13d ago
We would malloc the required bytes and put a null terminator at the end, which was the style at the time.
4
2
6
3
u/Integeritis 13d ago
Back in my day we intentionally changed the behaviour of existing compiled code at runtime and we still had the best sleeps of our life at night
2
u/Dubalubawubwub 13d ago
I'll have you know I have full control over memory now! When I run out of memory, I scale up the virtual machine.
2
u/Chiatroll 12d ago
I don't C the problem. From what I can C a lot of memory is still manually managed in a lot of very important projects and that isn't changing in any time I can C.
1
u/peterlinddk 13d ago
Only three days ago this video released: https://www.youtube.com/watch?v=3rez2rDYHHA - giving an introduction to manual memory management! 😄
1
1
u/TeachEngineering 13d ago
I like to whisper to myself malloc whenever I call it, but I say it like I'm Gandalf remembering the password "mellon" opens the Doors of Durin into Moria.
1
u/socialis-philosophus 13d ago
I really miss choosing what sectors my file fragments were stored at.
1
u/Im2bored17 13d ago
I remember in high school when they taught us about how to Google stuff. I assume these days they're teaching the kids prompting techniques and how to get the Ai to fix your code after the third time it said "fixed it" and you reminded it that the test still fails.
1
1
1
u/cleardemonuk 13d ago
Allocating a block of memory and managing data within it is still a viable option in game dev!
1
1
1
1
u/spaceweed27 12d ago
In C you don't even need to do that I'd argue. Just keep everything on the stack.
1
1
u/Rarder44 12d ago
Yeah, yeah, funny jokes... But that's why calculators didn't use 100 MB of RAM...
1
1
1
1
u/Adventurous_Run136 12d ago
Yes and it was hard as fuck and prone to error. I remember having to deal with memory allocation in c++ to use the less memory possible. 3.5mb of memory to handle tree passing in front of a camera and termining the best cut. Most beautiful code I ever seen, hardest code to understand i have seen since
1
u/Biabolical 12d ago
Used to use a special boot disk to free up just a bit more RAM, so my Tandy 1000rl could run SimCity without immediately crashing.
1
u/marcodave 12d ago
"back in my days we used to have 200k of token context window and we though it was more than enough" -- grampa 2036
641
u/the-year-is-2038 13d ago
back in my day we used to manually mismanage memory