Hi, I’m Derick. Welcome to PHP internals news, a podcast dedicated to explaining the latest developments in the PHP language. This is Episode 77. In this episode I’m talking with David Gebler about an RFC that he’s written to add a new function to PHP called fsync. David, would you please introduce yourself?

Hi, I’m David. I’ve worked with PHP professionally among other languages as a developer of websites and back end services. I’ve been doing that for about 15 years now. I’m a new contributor to PHP core, fsync is my first RFC.

What is the reason why you want to introduce fsync into the PHP language?

It’s an interesting question. I suppose in one sense, I’ve always felt that the absence of fsync and some interface to fsync is provided by most other high level languages, has always been something of an oversight in PHP. But the other reason was that it was an exercise for me in familiarizing myself with PHP’s core getting to learn the source code, and it’s a very small contribution, but it’s one that I feel is potentially useful, and it was easy for me to do as a learning exercise.

How did you find learning about PHP’s internals?

Quite the roller coaster. The PHP internals are very arcane I suppose I would say, it’s it’s something that’s not particularly well documented. It’s quite an interesting challenge to get into it. I think a lot of it you have to pick up from digging through the source code, looking at what’s already been done, putting together the pieces, but there is a really great community on the internals list, and indeed elsewhere online, and I found a lot of people very helpful in answering questions and again giving feedback when I first opened my initial proof of concept PR

Did you manage to find room 11 on Stack Overflow chat as well?

I did not, no.

I’ll make sure to add a link in the show notes and it’s where many of the PHP core contributors hang out quite a bit.

Sounds good to know for the future.

I read the RFC earlier today. And it talks about fsync, but it also talks about flush, or f-flush. What is the difference between them and what does fsync actually do?

That’s the question that will be on everyone’s lips when they hear about this feature being introduced into the language, hopefully. What does fsync do and what does fflush do? To understand that we have to understand the concept of the different types of buffering, an application runs on a system. So we have the application or sometimes called the user space buffer, and we have the operating system kernel space buffer,

And we’re talking a