Make concurrent examples actually run concurrently
If we end the `scoped` call with a semicolon, the `JoinGuard` will be dropped and not returned from the `map`. The thread will start up and we immediately block, making for a very expensive sequential loop.
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1 changed files with 4 additions and 4 deletions
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@ -430,7 +430,7 @@ fn main() {
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thread::scoped(move || {
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thread::scoped(move || {
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numbers[i] += 1;
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numbers[i] += 1;
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println!("numbers[{}] is {}", i, numbers[i]);
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println!("numbers[{}] is {}", i, numbers[i]);
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});
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})
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}).collect();
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}).collect();
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}
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}
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```
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```
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@ -442,7 +442,7 @@ It gives us this error:
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7 thread::scoped(move || {
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7 thread::scoped(move || {
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8 numbers[i] += 1;
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8 numbers[i] += 1;
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9 println!("numbers[{}] is {}", i, numbers[i]);
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9 println!("numbers[{}] is {}", i, numbers[i]);
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10 });
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10 })
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error: aborting due to previous error
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error: aborting due to previous error
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```
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```
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@ -483,7 +483,7 @@ fn main() {
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let mut array = number.lock().unwrap();
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let mut array = number.lock().unwrap();
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array[i] += 1;
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array[i] += 1;
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println!("numbers[{}] is {}", i, array[i]);
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println!("numbers[{}] is {}", i, array[i]);
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});
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})
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}).collect();
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}).collect();
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}
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}
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```
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```
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@ -543,7 +543,7 @@ fn main() {
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let guards: Vec<_> = (0..3).map(|i| {
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let guards: Vec<_> = (0..3).map(|i| {
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thread::scoped(move || {
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thread::scoped(move || {
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println!("{}", numbers[i]);
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println!("{}", numbers[i]);
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});
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})
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}).collect();
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}).collect();
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}
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}
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```
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```
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