On 2/17/21 10:38 AM, z wrote:
So i've upgraded one of my structs to use the more flexible delegates
instead of function pointers but when the member function tries to
access the struct's members, the contents are random and the program fails.
i've isolated the problem by adding writefln calls before calling the
delegate and inside the delegate(the functions are defined in the struct
as member functions, the delegate itself is set in the constructor) :
In the code that uses the delegate :
writefln!"test %s"(a, &a);
T b = a.d();//the delegate
While in the most used delegate :
writefln!"test2 %s %s"(this, &this);
The contents and pointers don't match(they're random, full of 0, -nan,
-inf and other invalid values), are they(delegates) supposed to be used
like this?
With structs and delegates, you have to be careful because structs are
copied easily, and using a delegate on a struct that is no longer in
scope is going to lead to memory corruption.
In order to properly ensure delegates are pointing to valid data, make
sure the struct is still not moved or overwritten, or it is allocated on
the heap.
-Steve
