Debugging D shared libraries

[Laeeth Isharc via Digitalmars-d-learn]

On Saturday, 19 September 2015 at 17:41:39 UTC, Laeeth Isharc 
wrote:
> On Saturday, 19 September 2015 at 10:45:22 UTC, Russel Winder 
> wrote:
>> Calling D from Python. I have two functions in D, compiled to 
>> a shared object on Linux using LDC (but I get same problem 
>> using DMD).
>>
>> The sequential code:
>>
>>     extern(C)
>>     double sequential(const int n, const double delta) {
>>       Runtime.initialize();
>>       const pi = 4.0 * delta * reduce!(
>>             (double t, int i){ immutable x = (i - 0.5) * 
>> delta; return t + 1.0 / (1.0 + x * x); })(
>>             0.0, iota(1, n + 1));
>>       Runtime.terminate();
>>       return pi;
>>     }
>>
>> works entirely fine. However the "parallel" code:
>>
>>     extern(C)
>>     double parallel(const int n, const double delta) {
>>       Runtime.initialize();
>>       const pi = 4.0 * delta * taskPool.reduce!"a + b"(
>>           map!((int i){ immutable x = (i - 0.5) * delta; 
>> return 1.0 / (1.0 + x * x); })(iota(1, n + 1)));
>>       Runtime.terminate();
>>       return pi;
>>     }
>>
>> causes an immediate segfault (with LDC and DMD.  I am assuming 
>> that the problem is the lack of initialization of the 
>> std.parallelism module and hence the use of taskPool is 
>> causing a problem. I am betting I am missing something very 
>> simple about module initialization, and that this is not 
>> actually a bug.
>>
>> Anyone any proposals?
>
> Btw have you looked at Colvin's prettypyd ?  It's a nicer way 
> to wrap things.  Just @pdef!() before functions, aggregates and 
> fields to wrap them.
>
> For demos, I should also think that showing Python code in one 
> Jupyter cell  calling D code in another is a pretty nice way to 
> show interop.  Just need to install the pyd Magic.    Your D 
> code can import dub libraries too.


In particular it should just work that way as PyD should deal 
with runtime initialization and the like.

https://github.com/DlangScience/PydMagic
https://github.com/DlangScience/PydMagic/blob/master/examples/test.ipynb
https://github.com/John-Colvin/ppyd