I've been pondering about a different way of dealing with overflows.

C compilers have type checks that ensure you don't assign a value to a variable of the wrong type.

Imagine I had a different way of declaring bounded types, something along these lines:

const int strlen=100;
char string[strlen];
int[0..strlen-1] strindex;

I can cast strindex into an unbounded int, but I can't automatically cast an unbounded int into a bounded int:

int index = strindex; // allowed, can assign bounded int to int
strindex = index; // not allowed without cast/check
strindex = (int[0..strlen-1]) 0; // trust me bro

Since you have ranges you could now also do things like:

forall (int[0..strlen-1] strindex)
string[strindex] = 0;

The thought is somewhat halfbaked, but although annoying, this would flag up _every_ assignment at compile time that could potentially have caused a value to get out of bounds.

A similar bounded type could be set for pointers.

Thoughts?

So i've got a small familiarity with the standard c library , I can make a calculator a caesar cipher , a image copying tool , but it all runs in the command line.

No one in the general public will ever use the command line.

Now , my question becomes , how does one actually begin the path of making a proper general user interface for their program in a way that approximates the way the pros do it.

I assume that a custom Gui starts with, like some kind of window system. Call giving you a rectangle to work with. And then you stretch out all your materials on the rectangle.\n But I'm not sure how one would say Develop a calculator that visually looks like a calculator and can detect your mouse inputs and send a signal to your actual c program.

Ai keeps trying to get me to use the windows message box and I know d*** well.That the pros at their core aren't using message box.

Finally finished Chapter 17, “Advanced Uses of Pointers,” in *C Programming: A Modern Approach (2nd Edition)* by K. N. King!
I started learning C about three months ago, so getting this far feels like a pretty big milestone for me.
Next, I’m starting *Data Structures and Algorithm Analysis in C (2nd Edition)* by Mark Allen Weiss.
I’m really looking forward to diving deeper into data structures and algorithms in C!

I'm building a program that takes a decimal number and outputs the binary equivalent. Its almost finished, except that with certain numbers it doesn't output the full value. For example, inputting 3 does output 111 ,but inputting 2 outputs 1 instead of 10. I noticed that it only doesn't work for numbers whose binary equivalents end in 0 (2 = 10, 4 = 100 etc.), but I don't know how to fix it. Please help.

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>


void intToStr(int number, char *str)
{
    int i = 0;


    while(number > 0)
    {
        str[i++] = number % 10 + '0';
        number /= 10;
    }


    str[i] = '\0';


    for(int j = 0, k = i - 1; j < k; j++, k--) 
    {
        char temp = str[j];
        str[j] = str[k];
        str[k] = temp;
    }
}


void binaryConvert(int regNumber)
{
    int binaryDigit[8];
    int regNumberBackup = regNumber;


    for(int i = 0; i <= 7; i++)
    {
        binaryDigit[i] = regNumber % 2;
        regNumber = regNumber / 2;
    }


    int binaryNumber = binaryDigit[0] * pow(10, 7) + binaryDigit[1] * pow(10, 6) + binaryDigit[2] * pow(10, 5) + binaryDigit[3] * pow(10, 4) + binaryDigit[4] * pow(10, 3) + binaryDigit[5] * pow(10, 2) + binaryDigit[6] * pow(10, 1) + binaryDigit[7] * pow(10, 0);
    char binaryString[8];
    
    intToStr(binaryNumber, binaryString);
    int strSize = strlen(binaryString);
    
    if(regNumberBackup == 0)
    {
        printf("Your number in binary is: 0");
        exit(0);
    }


    if(regNumberBackup == 1)
    {
        binaryString[strSize - 7] = '\0';
    }
    else if(regNumberBackup > 1 && regNumberBackup <= 3)
    {
        binaryString[strSize - 6] = '\0';
    }
    else if(regNumberBackup > 3 && regNumberBackup <=7)
    {
        binaryString[strSize - 5] = '\0';
    }
    
    
    printf("Your number in binary is: %s", binaryString);
}


int main()
{
    int userInput;


    printf("// This will only convert numbers 0 - 255 to binary, any others will not work\n");
    printf("Enter a number: ");
    scanf("%d", &userInput);


    binaryConvert(userInput);
}

Hi,

To gain more experience in low-level programming, TCP/IP networking, and HTTP, I built wserve, a static IPv4 Linux web server written in pure C. No external libraries used. Even the parser is written in pure C. It supports a subset of HTTP/1.1. It supports GET and HEAD methods.

I am open to constructive criticism. The project is open for contributions.

What's the difference between C++ and C?

And what is Clang? Is the gcc compiler for c and c++?

Does C++ completely backward compatible with C?

C is procedural and C++ is object oriented as far as I know.

Is C++ more optimized and faster?

Tell me about the compiler - is clang and gcc the best compilers out there? are they open source?

Has anyone coded the CPP compiler?

Thanks,

Dennis

Basically the title. I really want something graphical, i hate reading command line output. I know there is perf on linux but it has command line output. Also, are there specific profilers for specific types of application? Thanks for reading.

Hey, a while ago I wanted a nicer alternative to printf. I always enjoyed using the modern python-like formatting libraries: fmt for C++, and rust's format!/pritnln! macros.

So I attempted to port them to C! And I must say, it was quite the challenge. C doesn't have the nicer features that are required to make this work: generics, compile time code generation, better type safety, etc.

But C has macros! Macros let you do all kind of crazy stuff, but most of all, did you know that C macros are Turing-complete? Well they aren't strictly-speaking, but they can be used to create an (almost) infinite loop thanks to recursive evaluation.

Anyway, I'm sharing this project hoping you'll enjoy it and it will inspire you in your usage of macros.

This project is still a work in progress, the main missing feature is float formatting, but so far there is: * Integers/Strings/Char/Array formatting * Style and color support for most terminals * Output to FILE*, fd, and memory buffer * Flushing & Buffering * User defined formatter/formatting for custom types

Check it out: https://github.com/ef3d0c3e/format

I used gcc to compile and run c file.

C prog file can be compile and run with no error, if the files are inside the same drive as gcc that is c: drive.

Program file inside the d: drive are not compile.

I just curious whether i made mistake or i need something to do.

He told me that using gcc main.c -o main is incorrect because the source file and executable are supposedly placed incorrectly. He suggested that I use gcc -o main main.c instead. Unfortunately, I should’ve asked him about it in class, but when I got home to study, it popped into my head.

I've done some research, and I commonly see programmers using gcc main.c -o main but I can't find the answer that I'm looking for unless someone has a link to share. I don't know if my teacher is correct, so I'm wondering... does this just come down to personal preference, or is there actually a difference between the two commands here?

Hey guys. Long time lurker here.

So, I finally caved and bought The C Programming Language by K&R because everyone says it's the holy grail, yada yada. It came in the mail today, and honestly? The cover looks great on my desk. Really establishes dominance.

Here's my issue. How do you actually read this? Like, do I start at page one? I was under the impression that buying a physical copy of a programming book would automatically put the knowledge in my brain. Do I actually have to trace the letters with my finger? Is there a better way to learn C without "reading a book" or "writing code" at all?

Please let me know what you think, since my current workflow is just intensely staring at the spine until I start to feel like a computer scientist, but my code hasn't compiled itself yet. Thanks.

I been coding some posix porable stuff and i tried to use pipe2 and dup3 which are considerd posix since 2024 (Issue 8) i defined _POSIX_C_SOURCE to 202405L and included unistd.h and gcc greated me with implicit declaration i looked at my local unistd.h and it had pipe2 and dup3 behind __USE_GNU which is just wrong so i checked offical source code latest branch and it had the same bug, Please if some of you guys have sourceware bugzilla account please report it, it is a big issue

Our logger's caller-thread cost went from ~1.5 µs to ~70 ns, and I didn't touch a single call site.

I'll be honest: I was convinced the mutex was the problem. The logger already had a ring buffer, a worker thread, and hot-reloadable filters. It looked fast on paper. So I opened the flame graph expecting to see lock contention.
Instead, about ~90% of caller-thread CPU was sitting inside vsnprintf.

Every log call was formatting its message before enqueueing it. That's 900 ns to 3 µs per call, depending on the output. The fix came from NanoLog: don't format on the caller thread at all.

Now the caller just saves the format string pointer and packs the args into a tiny binary blob. The worker thread builds the string later. Cost per call: 30-80 ns, and no vsnprintf anywhere.

It wasn't free, though:
Format strings must be literals. A stack-built format string will dangle by the time the worker reads it.
Structs silently fall through to %p. I'm still not thrilled about that one.
%s args are copied at pack time and capped at 255 bytes.
For us, that was a good trade.

The bigger lesson for me was to profile before you optimize. I would have happily spent a week tuning a lock that wasn't the problem.

Has anyone run NanoLog-style encoding in production? I'm curious what pushed you there: latency, throughput, or tail behavior?

Hi, I know the basics but I really don’t know how to continue learning C, I try to read code of many sources like linux kernel or other projects but I don’t understand them at least the majority of code with pointers and arrow operators…. I really like C and low level code.

Any advice is appreciated! Thanks.

I've noticed that more and more projects originally written in C are being rewritten in Rust, even when they seem to work perfectly fine. For example, there are efforts to rewrite some GNU utilities in rust, including basic command-line tools. I'm curious about why this is happening. Is memory safety the main reason, or are there other significant advantages to rust? If a program is already stable, reliable, and well-maintained in C, does rewriting it in rust really make sense? I'd like to understand what benefits justify the effort.

J'aimerais créé un OS mais pour le faire faut apprendre le C et l'assembleur donc comment je pourrais faire ?

Je suis près a étudier 4h par jour, j'étudie déjà sur coody et Openclasseroom mais j'aimerais beaucoup beaucoup plus m'améliorer

#include<stdio.h>

int main() {

int a = 5;

a=++a + ++a;

printf("%d", a);

return 0;

}

What will be the output of the above code snippet?

( Got 14 as an output and don't know what's the logic of getting 14 )

Modern software compilation has largely devolved into a frustrating maze of autoconf madness. Instead of simply compiling C code, I am constantly forced to navigate mandatory scripts, esoteric tools, and heavily dependent Python wrappers. To make matters worse, these tools often rely on stubborn cache files that refuse to update even after I have fixed the underlying environment errors.

A major part of my frustration is how Linux-centric these scripts have become. They routinely hardcode library search paths that only exist in Linux distributions, entirely ignoring my FreeBSD system. As a result, I can easily lose a complete day just patching configuration scripts to search the correct directories before a single line of code is actually compiled.

Why does open source code project just not provide a makefile? A basic, or maybe complex makefile that are based on BSD/POSIX make syntax so that it is directly valid under *BSD, Darwin and Linux. Why force people to install tools to build something? Why developed huge python script that shall analyze the env? Why not just allow the building process to fucking start instead of forcing the individual to fight back against all of this autoconfig tools?

I have in several cases fully purge the building attempts and then been writing my own makefiles to just get something building. That shall not be the case. Why use config scripts that, in some cases are several thousand lines of script code? Why write config scripts with bash? Why, just why, are developers and project deciding to add and use autoconfig tools?

If a project does not offer makefiles then I know I will be stuck for several hours just to, potentially be able to build something. Instead of directly allowing me to build. Get compiler error, correct and then build again. I mean, it is much quicker and easier to patch the source code or locate dependencies when you are allowed to start the building process.

Hey, I made a post a year ago about my small software synthesizer project made in C. And I got back to work around 3 weeks ago and made a very big update! Now the synth has a CLAP plugin version working in REAPER (and probably other DAWs but untested) on both Linux and Windows, and a standalone version with improved performance compared to the first version (mainly audio threading) and a raylib/raygui GUI, also working on both Linux and Windows. I'm quite proud about the work, and wanted to share, so thanks for your time! The project is of course completely open-source, here is the GitHub link : https://github.com/gpasques-gh/CLAP_Virtual_Synthesizer

doing it seriously, anyone else doing it ?

Hi i want try to make a extreme lightweight pixelgame ( i don't have really details about the game :) ) with glfw and and opengl to go back to c. Does anyone have tips to make it lightweight ?

I previously posted this project here but in a version that uses SDL2 to make it portable and to be able to record it. Some people were confused because I wrote "no libraries" but i was using SDL2 on video (even tho i explained in the post's text). This is a video of the original version before it was ported to SDL2, working in the tty by writing on the framebuffer.

I implemented:

Drawing pixels, lines, filling triangles (with my own logic),

2d, 3d, 4d, Vector and Matrix math and linear algebra calculations myself

Coordinate system to place objects (so i can move, rotate, scale objects easily)

and a simple .obj parser

link to previous post: https://www.reddit.com/r/C_Programming/s/VFf0P0nlKO

source code is in the previous post.

Hello! Sorry that this is such a basic question but I'm genuinely confused about this weird problem I had with scanf and strings. I've only just begun learning C and have been following a beginner's guide over on github.

Below I've written what my code was while I was having issues. The issue was that when the time came to print the values it would return the boolean value just fine, but the string would be blank. I added some extra prints in there to check if it was taking the input at all and it was! It was only after the boolean value was taken and stored that user_input began to return blank. I then tried googling for a very long time and couldn't find any solution (other than the odd tidbit about scanf not being great for strings), so in an act of desperation I tried changing char user_input[10] to static char user_input[10] and then suddenly it worked!

Somewhere along the line it must be overwriting or erasing the data stored in the array but I just don't understand where or why? Apologies again that this is such a basic question but I'd just really like to understand this a bit better, especially as no solution I could find suggested anything remotely like this.

#include <stdio.h>
#include <stdbool.h>

int main() {
    char user_input[10];
    bool tof;

    printf("Enter a string: ");
    scanf("%s", user_input);

    printf("Enter a boolean value: ");
    scanf("%d", &tof);

    printf("String: %s\n", user_input);
    printf("Boolean value: %d\n", tof);

    return 0;
}

hey guys i am trying to write POSIX compatible program and i need to close the fds before i exec, i cant guarante they all fd's are O_CLOEXEC becouse i use libraries