On Sat, 11 Feb 2012 02:31:29 +0100, Ali Çehreli <[email protected]> wrote:
Sorry for the double-post; I have asked the same question on D.learn
earlier but I think this is more of a question to this forum.
Tested on Ubuntu 11.10 64-bit dmd.
The following program gets stuck during the writeln() call.
- Note that the foo() call alone works fine.
- Also note that the program works fine when there is no writeln() call
nor foo() call. All elements get processed in that case and the results
are ignored.
Am I using taskPool.map incorrectly or is this a bug? Can you help
identify where the problem may be? How is writeln() using the range
differently than foo() to cause this behavior?
import std.stdio;
import std.parallelism;
import core.thread;
int func(int i)
{
writeln("processing ", i);
return i;
}
void main()
{
auto results = taskPool.map!func([1,2,3,4,5,6,7,8], 2);
writeln(results); // <-- Gets stuck HERE
foo(results); // this works fine
}
void foo(R)(R range)
{
for ( ; !range.empty; range.popFront()) {
writeln(range.front);
}
}
Thank you,
Ali
Yeah, you have a deadlock in there, it's somewhat hidden though.
The issue is that writeln will take lock on stdout once. This will deadlock
with the lazy processing of the map range.
