On 5/6/20 2:49 AM, drug wrote:
06.05.2020 09:24, data pulverizer пишет:
On Wednesday, 6 May 2020 at 05:44:47 UTC, drug wrote:
proc is already a delegate, so &proc is a pointer to the delegate,
just pass a `proc` itself
Thanks done that but getting a range violation on z which was not
there before.
```
core.exception.RangeError@onlineapp.d(3): Range violation
----------------
??:? _d_arrayboundsp [0x55de2d83a6b5]
onlineapp.d:3 void onlineapp.process(double, double, long,
shared(double[])) [0x55de2d8234fd]
onlineapp.d:16 void onlineapp.main().__lambda1() [0x55de2d823658]
??:? void core.thread.osthread.Thread.run() [0x55de2d83bdf9]
??:? thread_entryPoint [0x55de2d85303d]
??:? [0x7fc1d6088668]
```
confirmed. I think that's because `proc` delegates captures `i` variable
of `for` loop. I managed to get rid of range violation by using `foreach`:
```
foreach(i; 0..n) // instead of for(long i = 0; i < n;)
```
I guess that `proc` delegate cant capture `i` var of `foreach` loop so
the range violation doesn't happen.
foreach over a range of integers is lowered to an equivalent for loop,
so that was not the problem.
Indeed, D does not capture individual for loop contexts, only the
context of the entire function.
you use `proc` delegate to pass arguments to `process` function. I would
recommend for this purpose to derive a class from class Thread. Then you
can pass the arguments in ctor of the derived class like:
```
foreach(long i; 0..n)
new DerivedThread(double)(i), cast(double)(i + 1), i, z).start();
thread_joinAll();
```
This is why it works, because you are capturing the value manually while
in the loop itself.
Another way to do this is to create a new capture context:
foreach(long i; 0 .. n)
auto proc = (val => {
process(cast(double)(val), cast(double)(val + 1), val, z);
})(i);
...
}
-Steve
