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I want to have my reference counted C++ object also managed in Lua callbacks: when it is held by a Lua variable, increase its refcount; and when the Lua variable is destroyed, release one refcount. It seems the releasing side can be automatically performed by __gc meta-method, but how to implement the increasing side?

Is it proper&enough to just increase refcount every time before adding the object to Lua stack?

Or maybe I should new a smart pointer object, use it everywhere in Lua C function, then delete it in __gc meta-method? This seems ugly as if something wrong with the Lua execution and the __gc is not called, the newed smart pointer object will be leaked, and the refcounted object it is referring would have leak one count.

In Perl that I'm more familiar with, this can be achieved by increase refcount at OUTPUT section of XS Map, and decrease refcount at destroyer.

I understand that after calling fork() the child process inherits the per-process file descriptor table of its parent (pointing to the same system-wide open file tables). Hence, when opening a file in a parent process and then calling fork(), both the child and parent can write to that file without overwriting one another's output (due to a shared offset in the open-file table entry).

However, suppose that, we call open() on some file after a fork (in both the parent and the child). Will this create a separate entries in the system-wide open file table, with a separate set of offsets and read-write permission flags for the child (despite the fact that it's technically the same file)? I've tried looking this up and I don't seem to be able to find a clear answer.

I'm asking this mainly since I was playing around with writing to files, and it seems like only one the outputs of the parent and child ends up in the file in the aforementioned situation. This seemed to imply that there are separate entries in the open file table for the two separate open calls, and hence separate offsets, so the slower process overwrites the output of the other process.

To illustrate this, consider the following code:

So, if I had a data table like this:

I am trying to define a subroutine in Raku whose argument is, say, an Array of Ints (imposing that as a constraint, i.e. rejecting arguments that are not Arrays of Ints).

Question: What is the "best" (most idiomatic, or straightforward, or whatever you think 'best' should mean here) way to achieve that?

Examples run in the Raku REPL follow.

What I was hoping would work

So I was fetching data from my database to print in a table however, it says that Class "App\Http\Controllers\User" not found. Here is the controller and here is how I will print the data

In C++20, we got the capability to sleep on atomic variables, waiting for their value to change. We do so by using the std::atomic::wait method.

Unfortunately, while wait has been standardized, wait_for and wait_until are not. Meaning that we cannot sleep on an atomic variable with a timeout.

Sleeping on an atomic variable is anyway implemented behind the scenes with WaitOnAddress on Windows and the futex system call on Linux.

Working around the above problem (no way to sleep on an atomic variable with a timeout), I could pass the memory address of an std::atomic to WaitOnAddress on Windows and it will (kinda) work with no UB, as the function gets void* as a parameter, and it's valid to cast std::atomic to void*

On Linux, it is unclear whether it's ok to mix std::atomic with futex. futex gets either a uint32_t* or a int32_t* (depending which manual you read), and casting std::atomic to u/int* is UB. On the other hand, the manual says

When using ls -l, I noticed that directories start with 2 hard links, and gain one for each subdirectory. I understand that the current directory link . counts as one link and the parent directory link .. of each subdirectory counts as a hard link, but:

I would like to extract the definitions from the book The Navajo Language: A Grammar and Colloquial Dictionary by Young and Morgan. They look like this (very blurry):

I'm trying to create a new variable based on some conditions. I have the following data: