Re: Problems with "shared"
On Sunday, 9 October 2016 at 21:32:23 UTC, ag0aep6g wrote:
On 10/09/2016 10:57 PM, jython234 wrote:
1. Where do I use the "shared" keyword?
What doesn't work is creating an unshared object of a class
that only has a shared constructor. To create both shared and
unshared objects, you need either two constructors or a `pure`
one.
class C
{
this() pure {}
}
void main()
{
auto u = new C; /* works */
auto s = new shared C; /* too */
}
Why this ins't in doc? :O I didn't know about using pure in this
way.
Re: Problems with "shared"
On 10/09/2016 10:57 PM, jython234 wrote:
1. Where do I use the "shared" keyword?
Mainly on data, I'd say. But I'm only dabbling in concurrency stuff.
I've done things like making
whole classes shared, which doesn't seem to make the member methods
shared either.
It does make the methods shared. It doesn't make the class type itself
shared, though. That is, you have write "shared" out when instantiating:
shared Foo foo = new shared Foo;
or
auto foo = new shared Foo;
or possibly
shared Foo foo = new Foo;
but not just
auto foo = new Foo;
or
Foo foo = new Foo;
Also this creates a million compiler errors when I try to
access the constructor from a non-shared function.
The host function being unshared shouldn't be a problem. Please show
code if that's really it.
What doesn't work is creating an unshared object of a class that only
has a shared constructor. To create both shared and unshared objects,
you need either two constructors or a `pure` one.
class C
{
this() pure {}
}
void main()
{
auto u = new C; /* works */
auto s = new shared C; /* too */
}
2. It seems that whenever I use shared I end up doing a ton of "unsafe"
casts from shared, and to shared and it makes me feel uneasy. I don't
think I'm supposed to be doing this.
If you're dealing with shared data directly, you're supposed to do that.
Ensure exclusive access, then cast shared away and do your stuff.
See std.concurrency and std.parallelism for more abstracted concurrency,
with less casts.
Re: Problems with "shared"
On Sunday, 9 October 2016 at 20:57:40 UTC, jython234 wrote: Hello, I've recently started a project in D, one which I plan to take advantage of concurrency. This means I will need to use the shared keyword. However, I have been having a few problems: 1. Where do I use the "shared" keyword? I've done things like making whole classes shared, which doesn't seem to make the member methods shared either. Also this creates a million compiler errors when I try to access the constructor from a non-shared function. 2. It seems that whenever I use shared I end up doing a ton of "unsafe" casts from shared, and to shared and it makes me feel uneasy. I don't think I'm supposed to be doing this. 3. Another concern I have is that I plan on using this project to introduce other people to D. These people will probably have some background with programming (such as Java), but will be new to the "systems" programming area. I like D because of how broad it can be, but one of the biggest problems it has is the "shared" issue with Thread local data. This could be hard for newcomers to learn. Any tips on how I could fix these problems? Instead of rewriting a book that already exist I'll just say that [1] should answer all your questions. However I disagree with your saying that you'll "have to use shared", D proposes Data Sharing concurency of course but Message Passing concurrency is reccomended [2]. [1]: http://ddili.org/ders/d.en/concurrency_shared.html [2]: http://ddili.org/ders/d.en/concurrency.html
Problems with "shared"
Hello, I've recently started a project in D, one which I plan to take advantage of concurrency. This means I will need to use the shared keyword. However, I have been having a few problems: 1. Where do I use the "shared" keyword? I've done things like making whole classes shared, which doesn't seem to make the member methods shared either. Also this creates a million compiler errors when I try to access the constructor from a non-shared function. 2. It seems that whenever I use shared I end up doing a ton of "unsafe" casts from shared, and to shared and it makes me feel uneasy. I don't think I'm supposed to be doing this. 3. Another concern I have is that I plan on using this project to introduce other people to D. These people will probably have some background with programming (such as Java), but will be new to the "systems" programming area. I like D because of how broad it can be, but one of the biggest problems it has is the "shared" issue with Thread local data. This could be hard for newcomers to learn. Any tips on how I could fix these problems?
