__delete

Destroys and then deallocates an object.

In detail, __delete(x) returns with no effect if x is null. Otherwise, it performs the following actions in sequence:

Calls the destructor ~this() for the object referred to by x (if x is a class or interface reference) or for the object pointed to by x (if x is a pointer to a struct). Arrays of structs call the destructor, if defined, for each element in the array. If no destructor is defined, this step has no effect.
Frees the memory allocated for x. If x is a reference to a class or interface, the memory allocated for the underlying instance is freed. If x is a pointer, the memory allocated for the pointed-to object is freed. If x is a built-in array, the memory allocated for the array is freed. If x does not refer to memory previously allocated with new (or the lower-level equivalents in the GC API), the behavior is undefined.
Lastly, x is set to null. Any attempt to read or write the freed memory via other references will result in undefined behavior.

Note: Users should prefer $(REF1 destroy, object) to explicitly finalize objects, and only resort to core.memory.__delete when object.destroy wouldn't be a feasible option.

@system

void

__delete

(

)

(

ref T x

)

Parameters

x T: aggregate object that should be destroyed

Examples

Deleting classes

bool dtorCalled;
class B
{
    int test;
    ~this()
    {
        dtorCalled = true;
    }
}
B b = new B();
B a = b;
b.test = 10;

assert(GC.addrOf(cast(void*) b) != null);
__delete(b);
assert(b is null);
assert(dtorCalled);
assert(GC.addrOf(cast(void*) b) == null);
// but be careful, a still points to it
assert(a !is null);
assert(GC.addrOf(cast(void*) a) == null); // but not a valid GC pointer

Deleting interfaces

bool dtorCalled;
interface A
{
    int quack();
}
class B : A
{
    int a;
    int quack()
    {
        a++;
        return a;
    }
    ~this()
    {
        dtorCalled = true;
    }
}
A a = new B();
a.quack();

assert(GC.addrOf(cast(void*) a) != null);
__delete(a);
assert(a is null);
assert(dtorCalled);
assert(GC.addrOf(cast(void*) a) == null);

Deleting structs

bool dtorCalled;
struct A
{
    string test;
    ~this()
    {
        dtorCalled = true;
    }
}
auto a = new A("foo");

assert(GC.addrOf(cast(void*) a) != null);
__delete(a);
assert(a is null);
assert(dtorCalled);
assert(GC.addrOf(cast(void*) a) == null);

// https://issues.dlang.org/show_bug.cgi?id=22779
A *aptr;
__delete(aptr);

Deleting arrays

int[] a = [1, 2, 3];
auto b = a;

assert(GC.addrOf(b.ptr) != null);
__delete(b);
assert(b is null);
assert(GC.addrOf(b.ptr) == null);
// but be careful, a still points to it
assert(a !is null);
assert(GC.addrOf(a.ptr) == null); // but not a valid GC pointer

Deleting arrays of structs

int dtorCalled;
struct A
{
    int a;
    ~this()
    {
        assert(dtorCalled == a);
        dtorCalled++;
    }
}
auto arr = [A(1), A(2), A(3)];
arr[0].a = 2;
arr[1].a = 1;
arr[2].a = 0;

assert(GC.addrOf(arr.ptr) != null);
__delete(arr);
assert(dtorCalled == 3);
assert(GC.addrOf(arr.ptr) == null);

__delete

Parameters

Examples

See Also

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