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Shafik Yaghmour

@shafik.bsky.social

960 followers 240 following 630 posts

Compiler Engineer clang front end. Interests: C++, C, and undefined behavior. Martial Artist, Book Worm and Dad. he/him Mastodon: https://hachyderm.io/@shafik Blog: https://shafik.github.io/ #cplusplus #compilers

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Shafik Yaghmour @shafik.bsky.social · Sep 10

C++ quiz #302

Answer here: hachyderm.io/@shafik/1151...

#Cplusplus
#Cpppolls

#302 Given the following in C++

struct S {
void f(int);
private:
void f(double);
};

void g(S* sp) {
sp->f(2); // Does overload resolution
// work even though f(double) is private?
}

Without checking:

A. Yes
B. No

2 10

Shafik Yaghmour @shafik.bsky.social · 6h

C++quiz #305

Answer here: hachyderm.io/@shafik/1153...

#Cplusplus
#CppPolls

#305 Given the following in C++

auto f();
int f(); // Well-formed?

Without checking:

A. Yes
B. No

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 30

#15 Spooky Halloween C++

👻🎃👻🎃👻🎃👻🎃👻🎃

On Halloween a parent ask their child what their favorite character in class was today

🐢
🐢

The kid said "char mutable teenage_ninja_turtle;"

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 2

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 29

#14 Spooky Halloween C++

👻🎃👻🎃👻🎃👻🎃👻🎃

How do you scare a C++ dev who is also an environmentalist

🚗
🚙

Almost Always Auto

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

2 2

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 29

#13 Spooky Halloween C++

👻🎃👻🎃👻🎃👻🎃👻🎃

What was the werewolf's favorite feature?

🐺
🐺

pack expansions

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 25

#12 Spooky Halloween C++

👻🎃👻🎃👻🎃👻🎃👻🎃

What was the werewolf's least favorite storage class?

🐺
🐺

static

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 1

Shafik Yaghmour @shafik.bsky.social · 6d

Retro C++ quiz #42 vector cast?

Answer here: hachyderm.io/@shafik/1153...

#CppPolls
#cplusplus

Retro C++ quiz #42

Given the following in C++:

#include <vector>

void f() {
(std::vector<float>)(5,2);
}

Without checking, is the code:

A. Well-formed
B. Ill-formed
C. Undefined Behavior

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 25

#10 Spooky Halloween C++.

👻🎃👻🎃👻🎃👻🎃👻🎃

What C++ features are devils and demons looking forward to the most?

👹
👺

Contracts and assumptions

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 1

Shafik Yaghmour @shafik.bsky.social · 7d

The Usual Arithmetic Confusions: shafik.github.io/c++/2021/12/...

#cplusplus

There are a lot of aspects of C++ that are not well understood and lead to all sorts of confusion. The usual arithmetic conversions and the integral promotions are two such aspects.
Certain binary operators (arithmetic, relational and spaceship) require their operands to have a common type. The usual arithmetic conversions are the set of steps that gets operands to a common type. While the integral promotions brings integral types smaller than int and unsigned int to either int or unsigned int depending on which one can represent all the values of the source type. This is one of the areas in C++ that comes directly from C, so pretty much all of these examples applies to C as well as C++.

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Shafik Yaghmour @shafik.bsky.social · 7d

"A small number of samples can poison LLMs of any size": www.anthropic.com/research/sma...

Black hats have to be trying (Why wouldn't they, the potential gains are large). If it's really this easy then likely malicious code is already making its way into real code bases, maybe at scale.

😱

#ai

In a joint study with the UK AI Security Institute and the Alan Turing Institute, we found that as few as 250 malicious documents can produce a "backdoor" vulnerability in a large language model—regardless of model size or training data volume. Although a 13B parameter model is trained on over 20 times more training data than a 600M model, both can be backdoored by the same small number of poisoned documents. Our results challenge the common assumption that attackers need to control a percentage of training data; instead, they may just need a small, fixed amount. Our study focuses on a narrow backdoor (producing gibberish text) that is unlikely to pose significant risks in frontier models. Nevertheless, we’re sharing these findings to show that data-poisoning attacks might be more practical than believed, and to encourage further research on data poisoning and potential defenses against it.

3 6

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 23

#9 Spooky Halloween C++

👻🎃👻🎃👻🎃👻🎃👻🎃

What potential C++ feature do vampires find least useful?

👻
👻

Reflection

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 1 2

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 23

#8 Spooky Halloween C++

 👻🎃👻🎃👻🎃👻🎃👻🎃

 Why are the input characters afraid of the Lexer?

 👻 👻

 They heard about maximal munch!

 👻🎃👻🎃👻🎃👻🎃👻🎃

 #cplusplus

2 1

Shafik Yaghmour @shafik.bsky.social · 8d

I got to use vestigial in a review today 🧐

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 23

#7 Spooky Halloween C++.

👻🎃👻🎃👻🎃👻🎃👻🎃

What are a ghosts favorite types?

👻
👻

bool and float

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

2 3

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 23

#6 Spooky Halloween C++.

👻🎃👻🎃👻🎃👻🎃👻🎃

What is a vampires favorite type?

👻
👻

std::byte

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 2

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 19

#5 Spooky Halloween C++.

👻🎃👻🎃👻🎃👻🎃👻🎃

Why did Igor make a bad C++ dev?

👻
👻

He keeps trying to throw the switch

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 4

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 7

#4 Spooky Halloween C++.

👻🎃👻🎃👻🎃👻🎃👻🎃

Why don't mummies use exceptions?

👻
👻

Because they are afraid of unwinding

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

3 4

Shafik Yaghmour @shafik.bsky.social · 13d

C++ Retro quiz #41

Answer here: hachyderm.io/@shafik/1153...

#CppPolls
#cplusplus

Retro C++ quiz #41

Given the following in C++:

struct B {
int x:4;
};

void f(int &x);

void b() {
B b1{1};

auto &[y] = b1; // A
y = 5; // B
f(y); // C
}

Without checking, the code is ill-formed (requires a diagnostic) at point:

A. A
B. B
C. C

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 7

#3 Spooky Halloween C++.

👻🎃👻🎃👻🎃👻🎃👻🎃

Why are C++ devs bad at halloween?

👻
👻

Because they all come wearing bit-masks

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 1

Reposted by Shafik Yaghmour

Shafik Yaghmour @shafik.bsky.social · Oct 6

#2 Spooky Halloween C++.

👻🎃👻🎃👻🎃👻🎃👻🎃

Why don’t the undead make good C++ programmers?

👻
👻

Because they don’t know how to end their lifetimes properly.

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

1 3

Shafik Yaghmour @shafik.bsky.social · 15d

Folks just assume they are right and get mad when I tell them know that is not right.

It is a lot more work to dig up the reputable sources that shows how wrong it is than for folks to just accept what the summary says.

This is direly bad for society.

Shafik Yaghmour @shafik.bsky.social · 15d

I have now been experiencing folks using LLM summaries to answer question and often they get the very high level stuff correct but get details that are important but maybe have less content or are controversial and therefore have a lot of just wrong information out there wrong.

1 1

Shafik Yaghmour @shafik.bsky.social · 15d

#1 Spooky Halloween C++

👻🎃👻🎃👻🎃👻🎃👻🎃

How do you curse an int?

👻
👻

You cast a hex on it:

int x = static_cast(0xB00);

👻🎃👻🎃👻🎃👻🎃👻🎃

#cplusplus

3 9

Shafik Yaghmour @shafik.bsky.social · 17d

"Other Countries Have Better Election Laws": www.electoral-vote.com/evp2025/Item...

- Ban All Corporate Campaign Donations:

- Limit Campaign Length

- Put Spending Caps in Place

- Have Campaigns Be Paid for With Public Funds

- Mandatory Voting

Other Countries Have Better Election Laws

Click on the map for the article

www.electoral-vote.com

Shafik Yaghmour @shafik.bsky.social · 20d

"Lawfare editor Benjamin Wittes reacts to the James Comey indictment": www.npr.org/2025/09/26/n...

This was a really strong interview and worth the listen.

Lawfare editor Benjamin Wittes reacts to the James Comey indictment

NPR's A Martinez speaks with Lawfare editor in chief Benjamin Wittes, a friend of James Comey, about the former FBI director's indictment on charges of obstructing justice and making a false statement...

www.npr.org

Shafik Yaghmour @shafik.bsky.social · 20d

"Leave Therapy to Humans": www.kqed.org/perspectives...

This feels like a very thoughtful perspective on why LLMs bots are not good therapists.

Bill Selig: Leave Therapy to Humans | KQED

Dr. Bill Selig weighs in on why AI does not make a good therapist.