Is there a way to flush a thread's message box other than aborting the thread? MailBox is private:

https://github.com/D-Programming-Language/phobos/blob/master/std/concurrency.d#L1778

On Thursday, 20 August 2015 at 15:25:57 UTC, Chris wrote:
> Is there a way to flush a thread's message box other than aborting the thread? MailBox is private:
>
> https://github.com/D-Programming-Language/phobos/blob/master/std/concurrency.d#L1778

flush from inside the thread? You could call receiveTimeout with a 0 timer in a loop until it returns false.

On Thursday, 20 August 2015 at 15:57:47 UTC, John Colvin wrote:
> On Thursday, 20 August 2015 at 15:25:57 UTC, Chris wrote:
>> Is there a way to flush a thread's message box other than aborting the thread? MailBox is private:
>>
>> https://github.com/D-Programming-Language/phobos/blob/master/std/concurrency.d#L1778
>
> flush from inside the thread? You could call receiveTimeout with a 0 timer in a loop until it returns false.

Yes, from inside the thread. I have a worker thread (with receiveTimeout) that is started when the program starts and sits there waiting for input. I naively thought this was a great idea, until I noticed that when input comes fast the mailbox grows and the bloody thread won't stop until all the items in the mailbox are processed. I was looking for something like `if (abort) { mailbox.flush(); }`

On Friday, 21 August 2015 at 10:43:22 UTC, Chris wrote:
> On Thursday, 20 August 2015 at 15:57:47 UTC, John Colvin wrote:
>> On Thursday, 20 August 2015 at 15:25:57 UTC, Chris wrote:
>>> Is there a way to flush a thread's message box other than aborting the thread? MailBox is private:
>>>
>>> https://github.com/D-Programming-Language/phobos/blob/master/std/concurrency.d#L1778
>>
>> flush from inside the thread? You could call receiveTimeout with a 0 timer in a loop until it returns false.
>
> Yes, from inside the thread. I have a worker thread (with receiveTimeout) that is started when the program starts and sits there waiting for input. I naively thought this was a great idea, until I noticed that when input comes fast the mailbox grows and the bloody thread won't stop until all the items in the mailbox are processed. I was looking for something like `if (abort) { mailbox.flush(); }`

void flushMailbox()
{
    bool r;
    do
    {
        r = receiveTimeout(Duration.zero, (Variant _){});
    } while(r);
}

You could optimise that to more efficiently deal with the actual types you're receiving, instead of making a Variant every time, but it's probably not worth it. The compiler might even optimise it away anyway.

On Friday, 21 August 2015 at 12:59:09 UTC, John Colvin wrote:
> On Friday, 21 August 2015 at 10:43:22 UTC, Chris wrote:
>> On Thursday, 20 August 2015 at 15:57:47 UTC, John Colvin wrote:
>>> On Thursday, 20 August 2015 at 15:25:57 UTC, Chris wrote:
>>>> Is there a way to flush a thread's message box other than aborting the thread? MailBox is private:
>>>>
>>>> https://github.com/D-Programming-Language/phobos/blob/master/std/concurrency.d#L1778
>>>
>>> flush from inside the thread? You could call receiveTimeout with a 0 timer in a loop until it returns false.
>>
>> Yes, from inside the thread. I have a worker thread (with receiveTimeout) that is started when the program starts and sits there waiting for input. I naively thought this was a great idea, until I noticed that when input comes fast the mailbox grows and the bloody thread won't stop until all the items in the mailbox are processed. I was looking for something like `if (abort) { mailbox.flush(); }`
>
> void flushMailbox()
> {
>     bool r;
>     do
>     {
>         r = receiveTimeout(Duration.zero, (Variant _){});
>     } while(r);
> }
>
> You could optimise that to more efficiently deal with the actual types you're receiving, instead of making a Variant every time, but it's probably not worth it. The compiler might even optimise it away anyway.

Wouldn't it be easier to have a library function that can empty the mailbox immediately? It's a waste of time to have all items in the mailbox crash against a wall, before you can go on as in

[
item1  // cancel
item2  ===> do nothing return;
item3  ===> do nothing return;
]

In parts I find std.concurrency lacking. Simple things sometimes need workarounds.

On Friday, 21 August 2015 at 14:35:53 UTC, Chris wrote:
> On Friday, 21 August 2015 at 12:59:09 UTC, John Colvin wrote:
>> On Friday, 21 August 2015 at 10:43:22 UTC, Chris wrote:
>>> On Thursday, 20 August 2015 at 15:57:47 UTC, John Colvin wrote:
>>>> On Thursday, 20 August 2015 at 15:25:57 UTC, Chris wrote:
>>>>> Is there a way to flush a thread's message box other than aborting the thread? MailBox is private:
>>>>>
>>>>> https://github.com/D-Programming-Language/phobos/blob/master/std/concurrency.d#L1778
>>>>
>>>> flush from inside the thread? You could call receiveTimeout with a 0 timer in a loop until it returns false.
>>>
>>> Yes, from inside the thread. I have a worker thread (with receiveTimeout) that is started when the program starts and sits there waiting for input. I naively thought this was a great idea, until I noticed that when input comes fast the mailbox grows and the bloody thread won't stop until all the items in the mailbox are processed. I was looking for something like `if (abort) { mailbox.flush(); }`
>>
>> void flushMailbox()
>> {
>>     bool r;
>>     do
>>     {
>>         r = receiveTimeout(Duration.zero, (Variant _){});
>>     } while(r);
>> }


Thanks by the way. This does the trick.

On Friday, 21 August 2015 at 14:35:53 UTC, Chris wrote:
> On Friday, 21 August 2015 at 12:59:09 UTC, John Colvin wrote:
>> [...]
>
> Wouldn't it be easier to have a library function that can empty the mailbox immediately? It's a waste of time to have all items in the mailbox crash against a wall, before you can go on as in
>
> [
> item1  // cancel
> item2  ===> do nothing return;
> item3  ===> do nothing return;
> ]
>
> In parts I find std.concurrency lacking. Simple things sometimes need workarounds.

yes, it would be better. Please file an enhancement request: https://issues.dlang.org

On Friday, 21 August 2015 at 17:05:56 UTC, John Colvin wrote:
> On Friday, 21 August 2015 at 14:35:53 UTC, Chris wrote:
>> On Friday, 21 August 2015 at 12:59:09 UTC, John Colvin wrote:
>>> [...]
>>
>> Wouldn't it be easier to have a library function that can empty the mailbox immediately? It's a waste of time to have all items in the mailbox crash against a wall, before you can go on as in
>>
>> [
>> item1  // cancel
>> item2  ===> do nothing return;
>> item3  ===> do nothing return;
>> ]
>>
>> In parts I find std.concurrency lacking. Simple things sometimes need workarounds.
>
> yes, it would be better. Please file an enhancement request: https://issues.dlang.org

Done.

https://issues.dlang.org/show_bug.cgi?id=14953