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by masklinn 4825 days ago
> Not really. If you use channels to communicate between goroutines, then the concurrency model is that of sequential processes

Except since Go has support for neither immutable structures not unique pointers, the objects passed through the channel can be mutable and keep being used by the sender. Go will not help you avoid this.

> That is, the default concurrency model militated by Go is not shared memory, but that of CSP. It's disingenuous to affix Go with the same kind of concurrency model used in C.

It's not, go passes mutable objects over its channel and all routines share memory, you get the exact same model by using queues in C.

> What's your point? Purity for purity's sake?

That the Go team has no issue breaking the rules they impose on others, so that point is irrelevant.
2 comments
fulafel 4825 days ago
> since Go has support for neither immutable structures not unique pointers, the objects passed through the channel can be mutable and keep being used by the sender. Go will not help you avoid this.

Channels are pass-by-value. If you pass a struct, it's copied, and both sides can mutate their own copies as much as they want.

You can get still bugs if you make channels of pointers (or have pointers in your message structs etc).

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masklinn 4825 days ago
> You can get still bugs if you make channels of pointers (or have pointers in your message structs etc).

Confirming that

> the objects passed through the channel can be mutable and keep being used by the sender. Go will not help you avoid this.

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burntsushi 4825 days ago
> Except since Go has support for neither immutable structures not unique pointers, the objects passed through the channel can be mutable and keep being used by the sender. Go will not help you avoid this.

I never claimed otherwise. But I do think you underestimate the utility of idioms.

> you get the exact same model by using queues in C.

No, you don't. C doesn't have lightweight threads, which means it can't support a useful CSP model of concurrency.

Just because Go allows shared memory doesn't mean its main concurrency model isn't CSP. Go doesn't force CSP on you, but that is nevertheless the primary concurrency model of the language.

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pjmlp 4824 days ago
> No, you don't. C doesn't have lightweight threads, which means it can't support a useful CSP model of concurrency.

Well there are a few libraries available for it.

And Windows C developers can make use of fibers.

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