Lu Pan

Working on distributed systems at Facebook. “uvdn7” is “lupan” rotated by 180.

[Lu Pan @uvdn7]

A really cool small piece of integer division code in `folly::BucketedTimeSeries` – https://t.co/HZOaeOzS6O.

[Lu Pan @uvdn7]

I wrote this post on the mental model for C++ coro in March, and found myself referring back to it often. Let me just post it https://t.co/ThMqvhEB94.

[Lu Pan @uvdn7]

Guice configuration is like makefile, and injection is like dynamic linking, but all in Java.

[Lu Pan @uvdn7]

Say there are 100 doors with 98 regular goats, 1 special goat and 1 car. You pick on door, then the host opens 98 doors with 98 goats behind them. These 98 goats happen to be all regular goats. Would you switch the door to maximize the probability of getting the special goat?

[Lu Pan @uvdn7]

OK I have my answer – I think you should switch.

[shachaf @shachaf]

My sister sent me this puzzle. It's so good!

[Lu Pan @uvdn7]

[new blog post] Access a function's return value in C++ scope guard https://t.co/hGs0Zht4ZP

[Lu Pan @uvdn7]

[new blog post] When `__cxa_pure_virtual` is just a different flavor of SEGFAULT https://t.co/a5sVcJ3I7S

[Lu Pan @uvdn7]

The gnu bash manual is great. It's well-structured and concise. Just wonderful. Lots of effort must went into it. https://t.co/EqGhXUGETe

[Lu Pan @uvdn7]

The list of talks of NEDB Day 2024 is out! https://t.co/9uDirdFmMc

I saw "Why Machine Learning for Automatically Optimizing Databases Doesn't Work" and was thinking Andy Pavlo would have something to say about it, then I realized that he's the one giving the talk! #NEDBDAY2024

[Lu Pan @uvdn7]

Not only the book Infinite Powers is fascinating (and I can’t put it down), I can feel @stevenstrogatz’s passion and love of the subject from the pages. The book is a wonderful gift. I am grateful.

[Lu Pan @uvdn7]

`async && closure && requires_explicit_memory_management && !borrow_checker` is really challenging. Borrow checker is really good to have especially when writing async code with closure! #rust

[Lu Pan @uvdn7]

[new blog post] Rust's early vs. late lifetime binding https://t.co/BkO6ylWdqU

[Lu Pan @uvdn7]

https://t.co/WC0VEII0OY is the answer. The actual capture algorithm is described here https://t.co/RcKqHuiBDk...

[Lu Pan @uvdn7]

It appears that the rust compiler tries really hard to infer how _and_ what to capture when it comes to closures. Do you think the following program compiles? #rust

[Lu Pan @uvdn7]

It does indeed compile in the playground https://t.co/gxMLUxrvkC. But it doesn't on Compiler Explorer (https://t.co/HLeJRnlgKx), or on my local machine. All tested on version 1.76.

[Lu Pan @uvdn7]

@iavins @MarkCallaghanDB is your guy

[Lu Pan @uvdn7]

Why a standalone redirect e.g. `2>/dev/null` gets interpreted as a `cat` command in zsh? The consequence is that then the shell will wait for the cat command which is waiting on stdin ... bash simply does nothing in this case.

[Lu Pan @uvdn7]

It looks like every value expression in rust behaves like xvalue in C++ – it has (or can have) an identity (so it can be borrowed) and can be moved from.

[Lu Pan @uvdn7]

`getcontext/setcontext` are not system calls but why there are getcontext(2)/setcontext(2) entries https://t.co/3zEaCHitED? `man getcontext.2` also exists although it shows the content for getcontext(3).

[Lu Pan @uvdn7]

If the function is declared extern, then this definition of the function is used only for inlining. In no case is the function compiled as a standalone function, not even if you take its address explicitly. https://t.co/2XRPVDqMu7

[Lu Pan @uvdn7]

How come gcc has `extern inline` with inline definition in the header without running into ODR (xmmintrin.h)?

[Lu Pan @uvdn7]

@davidtgoldblatt helped me! It is because of the __gnu__inline__ attribute which changed the behavior.