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Comment by megous | Hacker News Reader

Depends on what do you mean by window. If the window lives in a X server and you clone the client, window will obviously not get duplicated.

It's quite clearly defined what gets duplicated and what gets shared on clone()/fork(). There really is no ambiguity.

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I'm not saying a particular implementation is ambiguous as to what it does. Obviously any implementation will do something. I'm saying that fork as a concept is ambiguous as to what it should do.

You're forking a process, not the whole system. Sorry, but I fail to see the ambiguity. If the window is in the process as some framebuffer, it gets cloned too. That may not mean you'll get two windows on your monitor, because your display engine is HW thing, and not a process.

It's because you're thinking "it does X! it's not ambiguous!" but still missing that the question is over why it SHOULD do X instead of Y, not over whether it does X or Y. To a user, it sure as heck doesn't make sense to fork a process and still end up with one window for both of them. For lots of processes the process is its windows as far as the user is concerned.

Fork isn't an idea that users need to have. Devs may need to know what their OS API's fork() does. No-one else cares.

That's an argument for "I don't care about this", not an argument for "this abstraction is sensible".

Users don't fork processes, it's a low-level system thing.

Why repeat the same thing as the sibling comment posted an hour ago...?

Usually because you've had the browser open for a while and are seeing the state after the parent, but before the sibling comment was posted. At least that's usually why it happens for me; refreshing to see if someone else already has said what you want to say is rarely uppermost in my mind when a reply comes to mind.

Another possibility (pretty clearly not the case here) is when there are lots of replies: either you just miss it among the others, or ypu just can't be bothered to scroll down half a mile.

POSIX defines what a POSIX compliant fork() must do.

Yes it does.

So, do threads get duplicated or shared? Or something altogether different happens to them?

That's documented in man 2 fork.

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