On 1/10/19 12:15 PM, rx wrote:
alias SyncData = immutable(JSONValue);
void worker(string filename) {
SyncData data = filename.readText.parseJSON;
send(ownerTid, data);
}
void main(string[] args) {
spawn(&worker, args[1]);
writeln(receiveOnly!SyncData);
}
I'm trying to send this immutable(JSONValue) back to the main thread but
when trying to compile, I get the following error:
/usr/include/dmd/phobos/std/concurrency.d(764): Error: cannot modify
immutable expression ret.__expand_field_0
cc.d(15): Error: template instance
`std.concurrency.receiveOnly!(immutable(JSONValue))` error instantiating
Can anyone help out?
Looks like a long-standing bug (there are several related issues about
sending/receiving immutable data). The way std.concurrency.receiveOnly
works is it creates a temporary result, then puts the received item into
the result, and then returns it. But you can't copy an immutable into a
temporary that's already immutable.
e.g. it looks like this:
immutable int x;
x = 5; // error
I don't know if there's a specific "can't receive immutable data" issue
report, but certainly, you can add your issue to the list.
-Steve
