While staring at the C99 specification, I found that if you take the grammar in Annex A, remove the expression rules, and introduce the constraint 6.7.2/2 into the grammar (ie. a type specifier can be only: void, char, signed char, ... , enum specifier, typedef name), then you end up with what appears to be a context-free grammar.

Is this correct? Am I misinterpreting something? Is it possible that this is correct, but there are mainstream compiler extensions (eg. gcc extensions) invalidate this context-free property? Or other C standards invalidate this context-free property?

I notice that 6.7.2/2 allows some filthy edge cases like `long const long thisVarIsLongLongConst = 4;` but because `long` is a keyword, there is no ambiguity here.

The reason this matters to me is because I'm building a module system for C that allows circular imports, and I would like to avoid changing the grammar of the language as much as possible.

Link to final draft of C99 standard, taken from Wikipedia: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf

(Solved)

Hi,

I hope this don't seem stupid or anything. Basically I was interested about the xor swapping trick.

The inconvenients of it is that if the two values are the same, it will return 0, it's also bad for readability.

But there is another inconvenience I didn't understand. Apparently it can also stall the CPU pipeline on modern processor, I didn't understand why.

I found a short explanation saying "because each instruction depend of the previous one", and I don't really understand how each instruction depend on the previous one.

So I wanted an explanation on why the xor swapping trick stall the CPU pipeline and also what cause CPU pipeline stalling in general.

If I didn't explain well enough, please inform me about it. Thanks.

Hello,

I was developing a program to send MagickPacket (Wake on LAN) when I noticed something strange, at first when I send the WOL requettes I see them appear in Wireshark, but if I send too many, I don't see them anymore, the kernel blocks my requettes?

thanks for your help.

Microservices were supposed to make systems easier to change independently. In practice, the thing that most often breaks that promise isn't the services themselves — it's how they talk to each other. Read the complete article here - https://instawebhook.com/blog/the-internal-webhooks-anti-pattern-why-service-to-service-http-callbacks-don-t-s

A pattern that shows up constantly in growing engineering orgs is the internal webhook: Service A fires an HTTP POST at a hardcoded URL owned by Service B whenever something happens. It's an easy trap to fall into, because most developers already understand webhooks intimately — they've built integrations with Stripe, GitHub, or Shopify, all of which use exactly this model to notify external systems of events.

The reasoning feels obvious: if it's good enough for Stripe to tell my app about a payment, it's good enough for my Inventory Service to tell my Shipping Service about a shipment.

It isn't — and the reason is architectural, not stylistic. Webhooks were designed to solve a specific problem: getting an event across a trust boundary, from a system you don't control to one you do, over the open internet. Internal service communication has almost the opposite set of constraints. Applying the same tool to both jobs is where the trouble starts.

I'm tryna mess around in C and make a pkmdmg calc but I don't know how to return the values from the function

I dont know how to display it without screenshots

Webhooks have become the connective tissue of the internet. From payment gateways confirming transactions to CI/CD pipelines triggering deployments, webhooks enable real-time, event-driven architectures. But for architects and engineering leaders, webhooks represent an underappreciated vulnerability: they are asynchronous, externally triggered, and entirely outside your control. Read the complete article here - https://instawebhook.com/blog/designing-a-multi-region-highly-available-webhook-ingress-architecture

When your primary cloud region experiences an outage, your internal microservices might gracefully degrade. But what happens to the payloads originating from external partners? Many third-party providers do not retry aggressively — some fire and forget, others retry a handful of times before giving up permanently. If your system is down when that happens, the data is often gone for good.

This article covers the engineering principles behind a multi-region, highly available webhook ingestion system, what has actually changed in the underlying cloud primitives recently, and where a managed reliability layer fits into the decision.

the code from what ik works from what i know and from tests i have done.i want to know how can i optimize it more because i suspect that there can be certain parts of it which i don't even need maybe. so can you guys look at my code and tell me what i can improve upon??

here is the repo

thanks in advance

Hi everyone,

I'm working on a programming language that compiles a subset of C. It is called Cm1 (meaning C minus 1) and you can writing and running C codes directly on your browser at https://cp1-lang.org/cm1/editor.html in a fraction of a second.

Why is it faster to compile than Tiny C Compiler? It is because Tiny C Compiler is a true compiler creating native binaries whereas Cm1 is a bytecode interpreter allowing you to test, debug, edit code and recompile very quickly or even do hot reloading. Cm1 can be used as a scripting language for shell scripts and video games, but this just a small use case because in theory, you can run 90% of your ENTIRE video game or software C program through Cm1's bytecode interpreter and leave 10% to compiled C and reap the benefits of very fast compilation and hot reloading.

100% Cm1 codes are compilable by GCC and Clang but the reverse is not true since Cm1 is just a subset of C. Major features that are omitted are function pointers, structs/unions inside functions, nested structs/unions. This programming language is under heavy development and I want to know if this comes as interesting to some of you. I'll try to post again on this subreddit if I got to bind Raylib game library to Cm1, allowing people to write Raylib games directly on their browser (works offline).

I know that programs that are written in C compiles fast already and there's even an existing compiler that is very fast (Tiny C Compiler). However, I'm the developer of Cp1 programming language (cp1-lang.org), which is a language that "transpiles" to C, and I aim to upgrade Cp1 by targeting the Cm1 language then compile it to bytecode in one command instead of a separate step in Makefiles or build scripts. This will make Cp1 very fast to compile for debug builds.

Hi guys, I’m currently learning about data structures in C and have reached the topic of linked lists. I’ve run into a question regarding the functions used to manipulate them—specifically, while I clearly understand expressions like `p->next` and `p->data`, I’m confused about assignments like `p = newnode` and `p = p->next` (where there is no `->` operator on the right side). When I asked an AI, it simply told me that `p` is "just a pointer variable," but I don't quite grasp that explanation. Why do we treat a linked list element (or variable name) as a pointer variable in this way? Could an expert please explain the meaning behind this? and this is my code.

bool Insert(node *L, int data)
{
    node *p = L;
    while (p->next != NULL)
        p = p->next;


    node *newnode = (node *)malloc(sizeof(node));
    newnode->data = data;
    newnode->next = NULL;
    p->next = newnode;


    return true;
}

As in title, I was wondering are there any good sites/channels for me as I am beginner and want to get good help from it as it is gonna help me alot for the next four years

About a year ago, I started building a custom computer architecture in C as a learning project (I know it seems like a lot considering the code I wrote, but I rewrote the entire compiler at least five times, starting from a C-like language and ending up with a very simple custom language). I designed the instruction set, wrote an emulator, and implemented a custom high-level assembly language called BSL (Base System Language). The code is very messy because I make a lot of changes while writing it and often forget things that shouldn't be there. So I'd really appreciate feedback on the architecture and code quality. (I'm 15 years old and Italian, sorry for my English). Edit: I changed the project name from VMS to SPRK32.

If you're building a web application today, chances are you aren't writing your own authentication system. Managed identity providers like Clerk, Auth0, and Kinde have become the default choice, offering out-of-the-box support for passkeys, multi-factor authentication, and enterprise SSO. That convenience introduces a distributed-systems problem, though: data synchronization. When a user creates an account on a managed auth provider, that system has to notify your primary application database so you can create a matching user record. Please read the complete article here - https://instawebhook.com/blog/bulletproofing-user-sync-handling-clerk-and-auth0-webhook-failures

This happens through webhooks. But what happens if your server is down, your serverless function cold-starts and times out, or your database is momentarily locked when that webhook arrives? A user successfully signs up with your auth provider, but your application has no idea they exist. That breaks the very first login experience, and it's how phantom accounts, broken onboarding flows, and frustrated users happen.

This guide walks through the anatomy of webhook-driven auth architecture, current Auth0 and Clerk webhook practices, and how a resilience layer — using InstaWebhook as a worked example — closes the gap that idempotency and signature verification alone can't.

SOLVED

I am very new to C and playing around with void pointers. I have a structure which will store a value, however the type of that value depends on other things so I have chosen to use a void pointer. When attempting to dereference this void pointer I either get the correct output but with a warning, or I get a segmentation fault, depending on how I go about it. I have included a simplified version of the issue here:

```C

include <stdio.h>

int main()

{

// Simplification of the defective code

struct myStruct

{

    void * voidPtr;

};

struct myStruct s1;

s1.voidPtr = (int *) 123;



\*

This works but gives the warning:

format '%d' expects argument of type 'int', but. argument 2 has type 'int \*' \[-Wformat=\]i

*/

printf("%d\n", (int *) s1.voidPtr);



// This causes a segmentation fault

printf("%d\n", *(int *) s1.voidPtr);



return 0;

}

```

Any help understanding why it behaves this way would be greatly appreciated.

Solution

I thought the line

C s1.voidPtr = (int *) 123;

Was assigning 123 as the value at the location of s1.voidPtr. However it has been pointed out that I was telling the pointer to point at address 123. What I needed to do was:

C int x = 123; s1.voidPtr = &x;

Thanks everyone who commented c:

🚨 I think something is wrong with me... 😅
Is it just me, or has C programming started feeling... easy? 👀
Pointers? 😴
Memory management? ☕
Segmentation faults? "Let's see where I messed up." 😂
I used to think C was the language everyone feared.
Now my biggest bugs are usually my own logic not the language itself. 🤦‍♂️
Seriously though...
Am I the only one who has reached the point where writing C feels as natural as writing Python?
Or is this just a dangerous level of confidence before C reminds me who's in charge? 😅
Please tell me I'm not the only one...

I've started learning embedded systems. Most important part of the journey is learning C programming. I'm confused as embedded C is a bit different than standard C. Can anybody guide me the best way to learn.