Understanding SIGSEGV issues

[Nicholas Wilson]

On Saturday, 5 January 2019 at 10:52:48 UTC, Russel Winder wrote:
> I found the problem and then two minutes later read your email 
> and bingo we have found the problem.

Well done.

> Previously I had used File_Ptr* and on this occasion I was 
> using File_Ptr and there was no copy constructor because I have 
> @disable this(this). Except that clearly copying a value is not 
> copying a value in this case. Clearly this situation is what is 
> causing the destructor to be called on an unconstructed value. 
> But I have no idea why.

Could you post a minimised example? Its a bit hard to guess 
without one.

> The question now, of course, is should I have been using 
> File_Ptr instead of File_Ptr* in the first place. I am 
> beginning to think I should have been. More thinking needed.

 From the name, File_Ptr sounds like it is wrapping a reference to 
a resource. So compare with C's FILE/ D's File which is a 
reference counted wrapper of a FILE*. Would you ever use a File* 
(or a FILE**)? Probably not, I never have.