Is there a concept of "Happens-Before" in Rust?

Hi Rusteaceans,

I am coming from Java, and java provides a memory model, and i know for a fact , Rust doesn't.

I wanted to know how does Rust handle visibility issues?

In Java, a volatile variable access, synchronized provides a happens-before relationship

For example:

from Thread 1:

i = 10; j = 20;

done = true; // done is volatile

​

from Thread 2:

if(done == true)

assert i == 10 && j == 20;

​

here there is a happens before relationship when two threads access the same volatile variable.

I don't have to declare i and j as volatile, i believe, the JVM uses store/release and load/acquire memory barriers on \done\ variable to create this happens-before relationship.

How does Rust handle this?

Should i send all the variable of interest over a channel, which provides that happens before relationship?

struct State {

i: i32,

j:32

}

​

What about in shared memory concurrency?

any widely used technique you can refer me to ?

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Thanks!