In this video I will demonstrate how you can instruct the Visual Studio linker to produce a very minimalist executable You can get the reverse engineering software that I use in the video by running "winget install Rizin.Cutter"
Пікірлер: 236
@nirlichtman11 күн бұрын
- Forgot to mention that you can also pass the /O1 option to the compiler to optimize for size, but for such a small program this will have little effect - It is possible to make an even smaller executable with methods not covered in this video
@Name_cannot_be_blank11 күн бұрын
btw small correction, dont write "Windows.h" but "windows.h", as its actaully small, and this causes errors on a cross compile from linux, which is case-sensitive
@Hehenejcifre10 күн бұрын
Yooo NIR bro u going places I'm happy you grow channel organically only bro I watch ur assembly vid and loved the part when u said add wax 1 bro keep it up super super super hacker!
@ZipplyZane10 күн бұрын
For those wondering about how to make things even smaller, Dave Plumber makes a really small Windows executable to fit in a QR code.
@MK-bx8xv10 күн бұрын
@@Name_cannot_be_blank but the file is called "Windoes.h"?
@Flame_Dev10 күн бұрын
I don't know if anyone noticed, but the dialog box's title shows Error (5:51), so was the MB_OK parameter for the button to show OK?
@danutmh11 күн бұрын
It's not tiny , it's appropriately sized and it gets the job done , that's all that matters.
@Bluva11 күн бұрын
i'm sure that it has a great personality too
@Alguem38711 күн бұрын
Thats what she said
@fizipcfx11 күн бұрын
what is that pfp man i am seeing that everywhere
@masterchief558911 күн бұрын
@@fizipcfx Isn't that matrix?
@fizipcfx11 күн бұрын
@@masterchief5589 i did some digging and it looks like it is from deus ex, and a youtuber named maximillianmus was saying that subscribe to everyone who uses this pfp
@pixfri11 күн бұрын
A bit more precision about the end : Every NT executable has a small DOS program at the beginning just to print "This program cannot be run in DOS mode." We can see this by opening the executable in an hex editor. The DOS program starts with the letters "MZ" (the beginning of the header for a DOS program), then a bit after that, the actual program starts with the letters "PE" followed by two NULL bytes (0x50 0x45 0x00 0x00 in hex). Windows versions running on the NT kernel will just skip over the DOS program and start directly on the NT program part, but DOS based operating systems (Every MS-DOS version + Windows 1 -> Windows ME) will start at the beginning of the file and just execute the DOS program, saying "This program cannot be run in DOS mode." This was added back at the time when NT and DOS were both used to make sure NT programs weren't run on DOS operating systems.
@nirlichtman11 күн бұрын
Just a small correction - Also Windows Executables for Windows versions based on DOS (Windows 1 until Windows ME) start with a small MZ dos program and NE/PE afterwards - NE is an older predecessor for PE en.wikipedia.org/wiki/New_Executable
@robinweiland753311 күн бұрын
So just removing anything before the pe header won't interfere with the executable or is there any system within nt/windows that expects the DOS header? Maybe something like defender?
@GlorytoTheMany11 күн бұрын
Even funner fact: the DOS stub for the older NE executables actually said: "This program requires Microsoft Windows.", if I remember correctly. Technically you can change this string, or even replace the entire DOS stub with a legit useful DOS program, creating a so-called hybrid executable, but I haven't actually seen any linker that has this option. I'm also not sure if these strings are standardized, or just became adopted by all linkers because official MS tools use this exact text. UEFI applications are also PE executables, so they also need to have a DOS stub. The stub uses INT 21h/AH=09h to display the string and then quits with INT 21h/AH=4Ch (these are essentially DOS API calls).
@GlorytoTheMany11 күн бұрын
@@robinweiland7533 I once tried to remove the MZ stub just to see what happens, so my executable started with PE directly. Windows XP then refused to start the program, as it didn't recognize it as valid executable. So yeah, NT expects the DOS stub to be present (besides, I may have fucked up the offsets present in the header anyway by just brutally stripping the MZ stub). But even DOS would refuse to start an ill-formatted executable, unless it has the .COM extension, because then it would load and start it as a flat binary, which would lead to nonsensical results, likely leading to the computer hanging.
@sedrosken83111 күн бұрын
Windows 2000 is NT 5 -- you're likely thinking 95/98/98SE
@orcofnbu11 күн бұрын
It is just so cool. It feels fresh in the realm of the frameworks and libraries. People forgot how it felt having snappy programs. There is whole generation of developers does not care about any memory or size management.
@tweetyguy734711 күн бұрын
Snappy? Either way it’s snappy. It’s less than a megabyte
@JasminUwU11 күн бұрын
@@tweetyguy7347 100Kb can still be too big for some applications, like embedded
@JordanPlayz15811 күн бұрын
That is what happens when you have a lot more memory and processing power and storage space than back in the day, people will prioritize safety and/or readability over performance or use higher level languages so they can just focus on writing the program which I'd say makes sense even though I don't think things like electron make sense for many of the applications that use it
@vlc-cosplayer11 күн бұрын
Just say you don't feel like buying 16 gigs of RAM 💀
@Hexcede10 күн бұрын
@@vlc-cosplayer you don't need 16 gigs of RAM unless you're playing a big game that's going to use that RAM... Not very many do
@M1szS11 күн бұрын
A while ago i noticed that my C programs always are around 16KB, even though the contents in them differ a lot, and that video explain it perfectly
@UranG963011 күн бұрын
On the DOS thing, I actually had to update BIOS firmware on a Linux machine once, and only a Windows style .exe was availiable on the manufacturer's website. After reading around a bit, I found that I could rename and run that exec from a FreeDOS USB stick and successfully updated BIOS that way. It blew my mind a little bit, for that kind of hybrid executable to be possible.
@mikeyjohnson58889 күн бұрын
It blew your mind to be able to run DOS software on a DOS derivative?
@UranG96309 күн бұрын
@@mikeyjohnson5888 No, it blew my mind that you can have a single installer executable which can be run from DOS and at the same time provide a graphical install wizard on modern Windows.
@grappydingus10 күн бұрын
The "This program cannot be run in DOS mode." gave me an idea. One could probably create a dual-mode program. That will run in DOS and Windows.
@D0Samp10 күн бұрын
For example, the SETUP executable in Windows 3.1 worked that way. It could be run under DOS to change the configuration of Windows, but also under Windows itself.
@maxmuster700310 күн бұрын
DOS, Windows, Linux, MacOS in one quad mode executable?😂
@superduper791110 күн бұрын
You could hide an easter egg there
@grappydingus9 күн бұрын
@@maxmuster7003 Now we're talking!
@ismbks11 күн бұрын
what is this? binaries for ants??
@gametech410110 күн бұрын
I read this in Boris' voice
@red.doritos11 күн бұрын
Really pragmatic approach to the concepts I used to read in textbooks. You really did the practical even if it was a small demo, would love to see more videos like this one. You earned one subscriber. Thanks for making this.
@Smoth4810 күн бұрын
Very cool. Short and to the point, while still explaining everything you're doing fairly thoroughly. Thank you for the video!
@chasa885610 күн бұрын
The way you explain how stuff works is incredible, I really enjoyed watching the video and learning something new. You just earned a new subscriber!
@omran.alshehabi9 күн бұрын
This tiny explanation is amazing !
@cheesebusiness9 күн бұрын
What a great tutorial! I’m a web developer, I’ve written in C only a little and never programmed for Windows, but this video is super clear and interesting.
@neoqueto8 сағат бұрын
Explained in such a simple way. I learned something today.
@magnusm48 күн бұрын
Maining C# and learning about the unsafe keyword, pointers and then span. I learn more and more how absolutely vital memory allocation and use is. Especially in networking managing buffers and byte sizes. It's not just sending over as little as possible but managing the size of the buffer sent. It's a whole class subject's worth of study on it's own.
@Dominik-K11 күн бұрын
Great video, thanks a bunch for the explanations
@sdwone7 күн бұрын
This is actually VERY handy!!! Will be experimenting with this, when I can FINALLY stop playing with C# so that I can get back to the REAL programming language of C 😊
@leonardocaetano630710 күн бұрын
I didn't know about this cutter tool, super cool.
@ABCABC-sw8mh11 күн бұрын
The question I wanted to know a few weeks ago
@ashrasmun110 күн бұрын
I feel bad watching your videos. I feel like such a leech... So much great knowledge in such a great format.
@mythacker436510 күн бұрын
Thanks for the information 🙂
@wizard-pirate9 күн бұрын
Man, cutter is neat. Thanks for that recommendation. I'm trying to build a z80 based computer at the moment, and I've been having difficulty debugging my software.
@maciejk211 күн бұрын
love how You explain everything so easily and clearly :)
@DeviousMalcontent26 күн бұрын
The part of the application that says, "This program cannot be run in DOS mode." is referred to as the program stub, a program within a program if you will, you can modify this executable or even include a DOS version of your application inside of it by changing some compiler options.
@snooddagg927811 күн бұрын
You are very good at navigating windows…
@tuhkiscgibin662711 күн бұрын
I actually did this a few weeks ago with a win32 sokoban game I wrote. It yields good results even with mingw.
@Sevenisko9 күн бұрын
Fun fact: The MS linker has a /stub option, which lets you supply a custom DOS program.
@zyxwvutsrqponmlkh6 күн бұрын
This video has been done like 900 times before. But I've seen at least 800 of them so I think the algorithm knows me. AFIK dave the plumber has the high score for smallest win32 program.
@IRDOPEFISH11 күн бұрын
Thank you very much :)
@eitantal72611 күн бұрын
Given that the entry is now main, what's going to happen to bss segment and pre-assigned ram variables?
@djpcradock11 күн бұрын
To make it even smaller, don't forget about the awesome UPX exectuable compressor :)
@mertemr11 күн бұрын
And after put in 7z SFX archive 😅
@shitruns11 күн бұрын
upx has a 64kb limit for windows it's best to use crinkler and kkrunchy instead
@djpcradock10 күн бұрын
Never heard of Krinkler before. Thanks for the info! :)
@tropicaltrevor9 күн бұрын
To add to crinkler, which replaces your link.exe, there are also kkrunchy and squishy; which both take an existing exe and produce a smaller one. Like UPX (iirc) and crinkler they compress your program section and the exe itself is a decompressor that takes the rest of the binary and decompresses it in memory to then execute it. In a way this does make the exe smaller but does not truly reduce instruction count, and it can trigger antivirus protection becausd it means executing arbitrary memory as code that could not be statically checked for malware while it was compressed. Also unsure about how linking additional dlls, and compiling compressed dlls, would work there but statically linking should. Sorry for the info dump, they are fun tools to explore so check them out if you are going in a compression adventure :)
@shitruns9 күн бұрын
@@tropicaltrevor i somehow merged kkrunchy and crinkler together lmao. i mostly write demoscene stuff on linux my bad
@dtikvxcdgjbv79758 күн бұрын
Wow, great and utile.
@perz1val11 күн бұрын
The DOS header thing reminds me of the Cosmopolitan C library project by Justine Tunney. Have you seen it? I think analyzing programs written in it with cutter would be a cool video. I couldn't understand it well from the write-up, maybe you can explain its secrets better.
@jackfoster202811 күн бұрын
The smallest executable I can make with gcc is 652 bytes and that's it, can't go any lower than that.
@jakedeschamps445410 күн бұрын
Impressive! I'm curious what you did to achieve that. What compiler settings, and platform did you use?
@@jakedeschamps4454 I use Arch and go all out in Assembly. The gcc switches/settings are nostartfiles, nostdlib, static, fno-ident, nmagic and build-id is none
@bhavyakukkar11 күн бұрын
Do you use the same "tiling window manager" you made for windows in an earlier video, or a different one?
@nirlichtman11 күн бұрын
Yes, I use LightWM which is based upon the TWM I made in an earlier vid.
@Veso26611 күн бұрын
How would one make a hybrid executable that would work in DOS and Windows For instance a calculator When run in dos it would ask u questions, while ran in windows it would use winapi to display calculator
@CoderDBF8 күн бұрын
Based on someone else’s comment, Windows skips over the first few bytes that displays the DOS message, while DOS does not. So I imagine in theory if you could replace the message with a jump statement to a point in your application that deals with DOS specifically, and have your default main be the Windows entry point. This is just speculation, I’m not sure if it would work or not.
@Veso2668 күн бұрын
@@CoderDBF I mean if someone thought its a good idea for every program to also work in dos, even if it only displays a message then maybe people thought that at least in transition phaze you could have one executable Then there has to be a compiler that can produce hybrid executable I mean why would win32 apps have a separate WinMain entry point WinMain for windows main for dos
@YilmazDurmaz9 күн бұрын
nice to see the assembly code. I am learning assembly, and the book I use has chapters to work on linux. being a giant C program, Linux programs (at least from late 90s) uses stack based parameters passing. Here, message box function does not use stack. instead it uses registers. I now wonder if it is because of 64bits, or it is the way windows differs from linux. (though it still increases/decreases stack pointer rsp)
@nirlichtman9 күн бұрын
The parameters are passed according to the calling convention, in this case the registers are used instead of the stack because of the x64 calling convention used.
@user-tw9tt3lb3y11 күн бұрын
YES finally windows! i was looking for this video! thank you so much Nir! does Cutter work only with C?
@nirlichtman11 күн бұрын
Cutter works with many different binary file executable formats and is agnostic to the higher level programming language (or assembly) that they were originally written in.
@Raphipod10 күн бұрын
Nice video! Can you do a sort-of tutorial video on how to properly install Windows 10 with debloating tips / removing all the stuff that you don't need? You might just use the Home/Pro edition of Win10. Few people also suggest installing the 2021 LTSC version that has no bloat - but it isn't legit because many circument the activation with an external script (bc it's expensive if you do it the legitimate way). Many people are using an unofficial ISO downloaded from the internet that guarantee speed, reliability bla bla... but those ISOs can't really be trusted. Maybe you could also throw in some open-source applications that are alternatives for system apps (like the old Files app you have).
@nirlichtman9 күн бұрын
Yah I recently started using winfile and it's very nice (it's the original file manager from Windows 3.1, Microsoft open sourced it and it's maintained on Github) The debloating Win10 is a good idea for a future video, I will add to my list
@wilk8511 күн бұрын
hi, could you please make some longer video on creating kernel modules/drivers under linux? or could you please create some C videos on some 'hacky' way to use it?
@brandonchannell786510 күн бұрын
Will the program run on Windows if you remove the DOS portion of the executable?
@jasdfff77011 күн бұрын
Very nice video!! This happens with other compiles as well (gcc, clang)? Or only with the windows compiler "cl"?
@alexandermaximilianoetken726511 күн бұрын
You can do that. The linker flags can be a bit different.
@nirlichtman11 күн бұрын
I checked with GCC as well and it also by default adds some C library boilerplate to the executable
@jasdfff77011 күн бұрын
Thanks!
@CamaradaArdi10 күн бұрын
Could you do a follow up video explaining what things is setting up to use libc that takes +100KB?
@Mittzys11 күн бұрын
I'd like to see the cutter path for the DOS mode
@akta19848 күн бұрын
My tiniest exe had 2bytes. It was to turn on PC speaker. ❤
@milasudril11 күн бұрын
How does it deal with the stack after returning from main? If you bypass the start routine on Linux like so _start: ret it will crash with a sigsegv, because there is no valid address to return to at this point. In this case, you have to issue the _exit syscall. On Windows, that would correspond to ExitProcess.
@ItsCOMMANDer_11 күн бұрын
good question! imma install hidra and look into it, will update as soon as done
@GeorgeTsiros9 күн бұрын
@@ItsCOMMANDer_ the exact same way. it even accepts the return value from the entry point.
@Crux1618 күн бұрын
That’s me in a nutshell - “a little more useful than nothing,”
@newton-3428 күн бұрын
You forogt to strip the symbols from the binary, that's the reason why a hello world is comparatively huge. Excluding the C standard library is not a good idea IMHO, because you won't have printf for debigging, exit codes for your main function and basic convenience methods like string to int conversion. Thanks though for sharing Cutter, it seems like a very nice piece of software
@nirlichtman8 күн бұрын
The binary in the video does not contain symbols (you can see in the functions list in cutter it does not pick up any symbols). Unlike Unix systems, on Windows symbols are not saved in the main binary but they are saved aside in a .pdb file. By default, when compiling with Visual Studio Build Tools, cl works in release mode and thus no symbols and debugging information is generated unless a special flag is passed. There exist many Windows API functions which can come in place of C lib functions, for example instead of printf, WriteConsole can be used. And for string to int there exists RtlCharToInteger learn.microsoft.com/en-us/windows/win32/api/winternl/nf-winternl-rtlchartointeger Indeed, in most cases it is useful to also use the C lib for the convenience, but in some cases, it can be useful for example for very simple programs to only use Windows API if desired, it can also be a good learning experience.
@overbored13378 күн бұрын
Isnt WriteConsole just a file write to stdout? And I also think that Windows have the api wsprintf which combined with WriteConsole would be a complete printf
@newton-3428 күн бұрын
@@nirlichtman Thanks for sharing! Yeah, I was wrong... I just tested the /link /entry:main option and it shrinks the binary from 86kB to 1.5kB on my machine. And even the exit code is working just fine. Turns out, Windows is wildy different than Linux. But it's important to realize that stressing about 86k of library binary size isn't helpful for most developers. Though I personally do not like the Windows API and find its documentation very hard to understand, I agree it can be a great learning experience to use only Windows API functions instead of the C runtime. Your videos are very nicely produced, keep up the good work!
@nirlichtman8 күн бұрын
@@newton-342 Thanks!
@A1rWaxta4 күн бұрын
I complie this simple function with gcc and clang with -e flag, set to my main funciton, and output still contains std lib stuff, for both compilers. What other flags should I use?
@alch3myau6 күн бұрын
Soon as I saw edge on the desktop I paused, commented and closed.
@kaankarakoc768011 күн бұрын
thats very cool can we decrease the size of executable more ? I am waiting for new videos
@conrad4211 күн бұрын
There are 2 good videos from Dave's Garage about that. He got it down to 800-600 bytes :)
@kaankarakoc768011 күн бұрын
@@conrad42 thanks, and do you have any idea how the shell codes are being produced bc they are so small yet for example they can establish connections l wonder also how they are working
@conrad4211 күн бұрын
@@kaankarakoc7680 shell code is a script language, which needs another executable (interpreter) to be run. Shell scripts mostly just orchestrate other executables. C is a compiled language and you get a standalone executable. Is this understandable?
@itshoitshoify9 күн бұрын
Thanks! Just a small question - what are the downsides of using this flag? I suspect things such as losing Canary protection and buffer overflow detection. Is that correct?
@ANoBaka3 күн бұрын
So without the C entry point, you cannot do things like import stdio.h and call fprint?
@cocusar10 күн бұрын
can you do a demo of a different dos stub inside an exe?
@nirlichtman8 күн бұрын
That's a good idea, I will add to my list (might do this as part of a future video) :)
@user-lg2hl7hr3j11 күн бұрын
can you please fix the big icon small filename problem it hurts my eyes too and will be a great video topic
@tomasvolko994410 күн бұрын
DOSBOX: set blaster=220 etc. I remember this from DOS times. I hated this line and I used to delete it everywhere.
@kyrylosovailo16905 күн бұрын
But what about merging all pages (.data, .text, etc) to one?
@Spiderfffun11 күн бұрын
"winget package manager" **uses vim** I don't understand how you are not a linux user
@javierflores0911 күн бұрын
There's nothing wrong with using Windows, nowadays even if you feel the need to use linux for something, WSL makes up for it so it isn't much of a big deal. Besides, if I were to be this knowledgeable about windows and its various APIs, I sure as hell would prefer it lol
@shallex574410 күн бұрын
he is
@shallex574410 күн бұрын
@@javierflores09 other than the fact that it is proprietary and malware, i agree there is nothing wrong with using windows
@sebas11tian10 күн бұрын
Go developers 👀
@RealYukiSan7 күн бұрын
making toy android system would be interesting! ^^
@sussyGaymer11 күн бұрын
my hello world is 2048 bytes (could be lower if i messed with the alignment)
@justinnamilee9 күн бұрын
I'm running out of ways to say "Neat", maybe fantastique!
@andutei10 күн бұрын
"we're gonna use the W version so that we are not limited to ascii characters", proceeds to use only ascii anyway🤪
@nirlichtman10 күн бұрын
😂 I didn't mention this on the video, but it's also a better practice to use the wide char versions of Windows API functions in any case, since the Windows Native API functions that a lot of these APIs call work with wide char so when you call the ASCII versions of Windows API functions, they go through a conversion to wide before continuing to the native API.
@MattIsTheCat9 күн бұрын
Can you make an even smaller executable in Assembly?
@sdjhgfkshfswdfhskljh33606 күн бұрын
Yes.
@mlewellyn9 күн бұрын
I watched mostly because I have always had a question I've never bothered to answer for myself 😅 Unfortunately, the video didn't cover it: does WIN32_LEAN_AND_MEAN change the binary size? Perhaps one of these years I'll bother to find out 😹
@GeorgeTsiros9 күн бұрын
considering that that is checked only at one exact #ifndef in the windows' SDK (line 193 in windows.h), which is not #included in this example, i can say "not at all"
@sdjhgfkshfswdfhskljh33606 күн бұрын
Most likely, no. But it makes compilation faster (in case anyone is still concerned about that).
@angelffg11 күн бұрын
woow Nir, this is great!!!!! How do you find out about that knowledge? Do you read any specific C books? You are a genious!!! Nirk please, a video to use JSON in C where we can see how to process it and how to generate it. Thanks for sharing and please more videos like this!
@GeorgeTsiros9 күн бұрын
He read. Documentation, compiler/linker options, etc. Nothing in this is special to C.
@vitskr111 күн бұрын
Holy shit man, +39C? Where do you live, Venus? :)
@nirlichtman7 күн бұрын
😂 Crazy heat wave on that day
@krimzon6537 күн бұрын
I get many "LNK2001 unresolved external symbol" errors for many functions like "memcpy" and "rand"
@D0Samp6 күн бұрын
Changing the entry point not only omits the startup code, but the whole C standard library, only leaving you with the parts of the Win32 API you explicitly link with. You may want to link to the UCRT (included since Windows 10, an update to the classic MSVCRT) instead of the Visual Studio runtime for a smaller C program.
@krimzon6536 күн бұрын
@@D0Samp Thank you. I'll look into it. Or just have my own memcpy in the code. Thanks again
@noahwaaga507910 күн бұрын
Is that a windows tiler?
@nirlichtman10 күн бұрын
Yes, I started a TWM project for Windows called LightWM
@VaclavNemec7011 күн бұрын
oh, it's msvc...
@king1king2king38 күн бұрын
Is that applicable to C++ as well?
@sdjhgfkshfswdfhskljh33606 күн бұрын
Yes, but you will need to reimplement even more parts of standard library than for C case.
@andersonklein358710 күн бұрын
This reminds me of situations like when people are like: "I wonder why my Python program takes so long to load, it's only a few lines of code" The few lines: "import xawerfuaefrhiwethiwerragbesgbsrebgerbgiesgersbgsergerg... do simple thing, return x"
@SuzukaTheBest11 күн бұрын
what size second program with MessageBoxW was?
@SuzukaTheBest10 күн бұрын
@kokokokosin yes
@EionRobb10 күн бұрын
The `dir` from dosbox said it was 3072 bytes, so 3kB
@SuzukaTheBest10 күн бұрын
@@EionRobb thanks
@zawadhyaa11 күн бұрын
next one on Linux From Scratch, please!
@nirlichtman7 күн бұрын
Planned :)
@zawadhyaa7 күн бұрын
@@nirlichtman thanks!
@jackkendall642011 күн бұрын
Subscribe for more programming videos, and thanks for watching.
@GuildOfCalamity10 күн бұрын
I actually never notice since space is cheap these days... maybe if it were 1981 I would care.
@shallex574410 күн бұрын
it's the principle of the matter
@andreujuanc9 күн бұрын
Hope that temp showing is not in Celsius
@nirlichtman8 күн бұрын
😂 We had a serious heat wave
@HDJess5 күн бұрын
But what happens if you actually allow an NT .exe to run on DOS?
@nirlichtman5 күн бұрын
It runs the DOS stub section of the NT .exe, which in most cases is a simple DOS program that prints a message saying that it cant run on DOS (as demonstrated in the end of the video)
@HDJess5 күн бұрын
@@nirlichtman let me rephrase, since it got misunderstood. What happens if you remove the stub and correct the exe to not run into errors, then attempt to run in DOS?
@DELOREAN38910 күн бұрын
will it run on my 486 ? 🤔 asm when ?🤓
@sdjhgfkshfswdfhskljh33606 күн бұрын
Yes, if it will be built with Visual C++ 6 and /filealign:512 option.
@Mikee51211 күн бұрын
`:colorscheme desert` crew!
@mlewellyn9 күн бұрын
torte ftw 😂
@thesushifiend10 күн бұрын
So it’s a lie. This program CAN be run in DOS mode because it IS running in order to print the message.
@mlewellyn9 күн бұрын
No, the program written isn't running in DOS mode, just a bit of boiler plate to let you know. Just like the "Non-bootable disk" boot sector messages of days of yore: obviously it booted to a message, but it isn't doing what the user was trying to do. So both are correct messages.
@sdjhgfkshfswdfhskljh33606 күн бұрын
I was expecting to see 512 bytes or smaller.
@LukJestem10 күн бұрын
it's not really related that much to this video but from what i see, u know linux way better than me why do u still use windows? is it a personal preference? or sth else? waiting for the year of linux desktop :3? just curious
@nirlichtman9 күн бұрын
I find Windows more comfortable as my main desktop
@MPSoC9 күн бұрын
COM executable
@D0Samp10 күн бұрын
Isn't this program malformed? You may omit the whole C standard library including the default startup code, but you need at least one call to ExitProcess (same as _exit on Linux) to cleanly exit the program without crashing.
@D0Samp10 күн бұрын
Apparently this works because the entry point function returns into the function for spawning threads (BaseThreadInitThunk in kernel32) which exits the thread that it was started on, and a process will exit if it has no more threads.
@GeorgeTsiros9 күн бұрын
you're calling ret from a function. How could it possibly crash?
@D0Samp6 күн бұрын
@@GeorgeTsiros Unlike the main function, which is usually called by the startup code of the C library, an entry point function is not guaranteed to have a valid return address on the stack. But because threads are meant to return a status code and the main thread on Windows is started the exact same way as additional ones, it still works.
@GeorgeTsiros6 күн бұрын
@@D0Samp the entry point is entered by calling into it. No matter what it is, it will have a valid return address. yes?
@albaropereyra8 күн бұрын
Vi? Really?! It's 2024 time to run vi inside emacs lol
@AqoCyrale11 күн бұрын
מגניב
@Yazan_Majdalawi9 күн бұрын
💩
@mathgeniuszach10 күн бұрын
C/C++: Only pay for what you use! Windows: Yeah just let me do a bunch of setup first.
@jopa1999110 күн бұрын
It's not Windows, it's C runtime. Any C runtime must be initialized so your system APIs (memory, files, threads) can be wrapped efficiently inside C standard library. libsystem, glibc, musl etc. do this stuff too, your real entry point on Linux/Mac is also not main. Wanna see real bloat shit - dig into exception ABI on both Windows and POSIX :)
@kipchickensout11 күн бұрын
bro said ksor
@GeorgeTsiros9 күн бұрын
and "d.i.r." but we're not judging. That's how he learned to say it.
@chrischoir359410 күн бұрын
what is the real point of this?
@boy_deploy10 күн бұрын
Learning ❤
@chrischoir359410 күн бұрын
@@boy_deploy thanks, what I was asking is, from a technical perspective does this speed up the program? thanks
@Nikola95inYT10 күн бұрын
I suppose this can be used to write malware.
@boy_deploy10 күн бұрын
@@chrischoir3594 It definitely speeds up the program startup and the size of final executable file. Some even go as far as removing the C runtime library to eliminate the bloat.
@boy_deploy10 күн бұрын
Correction: *and lessen the size of final executable
@tomasvolko994410 күн бұрын
I remember the time when DOS stub was used as a DPMI loader and aplication got access to whole memory not just 640 MB.
@Kyoz9 күн бұрын
🤍
@cheesebusiness9 күн бұрын
Windows is just a fancy plugin for DOS
@MrAdamo9 күн бұрын
i can make any exe 1kb in windows by clicking "Create shortcut"
@MelroyvandenBerg11 күн бұрын
who is using Windows anyways still? lol
@-x21-11 күн бұрын
Roughly 73% of all computer users.
@shallex574410 күн бұрын
people who don't know anything about computers
@Mikewee7777 күн бұрын
Writing C code on windows is still valued but Windows 11 is the worst operating system they have made so far. It is worse than Vista.
@-x21-7 күн бұрын
@@Mikewee777 I'd argue later vista service packs are better than every windows after 7.
@mzakyr4211 күн бұрын
what about assembly? im using fasm that just ret and its 121 bytes (source code 67) edit: i use linux here is the output of xxd 00000000: 7f45 4c46 0201 0100 0000 0000 0000 0000 .ELF............ 00000010: 0200 3e00 0100 0000 7800 4000 0000 0000 ..>.....x.@..... 00000020: 4000 0000 0000 0000 0000 0000 0000 0000 @............... 00000030: 0000 0000 4000 3800 0100 4000 0000 0000 ....@.8...@..... 00000040: 0100 0000 0100 0000 0000 0000 0000 0000 ................ 00000050: 0000 4000 0000 0000 0000 4000 0000 0000 ..@.......@..... 00000060: 7900 0000 0000 0000 7900 0000 0000 0000 y.......y....... 00000070: 0010 0000 0000 0000 c3 .........
@nirlichtman11 күн бұрын
That is not executable under Windows (since it is an ELF format), try linking the code to be a PE format (the binary starts with the magic MZ) and x64 architecture
@androth150211 күн бұрын
@@nirlichtman it would be interesting to see how small a binary we can get from the cosmopolitan compiler.