destroy

Destroys the given object and optionally resets to initial state. It's used to destroy an object, calling its destructor or finalizer so it no longer references any other objects. It does not initiate a GC cycle or free any GC memory. If initialize is supplied false, the object is considered invalid after destruction, and should not be referenced.

  1. void destroy(T obj)
  2. void destroy(T obj)
  3. void destroy(T obj)
    void
    destroy
    (
    bool initialize = true
    T
    )
    (
    T obj
    )
    if (
    is(T == interface)
    )
  4. void destroy(T obj)
  5. void destroy(T obj)

Examples

Reference type demonstration

1 class C
2 {
3     struct Agg
4     {
5         static int dtorCount;
6 
7         int x = 10;
8         ~this() { dtorCount++; }
9     }
10 
11     static int dtorCount;
12 
13     string s = "S";
14     Agg a;
15     ~this() { dtorCount++; }
16 }
17 
18 C c = new C();
19 assert(c.dtorCount == 0);   // destructor not yet called
20 assert(c.s == "S");         // initial state `c.s` is `"S"`
21 assert(c.a.dtorCount == 0); // destructor not yet called
22 assert(c.a.x == 10);        // initial state `c.a.x` is `10`
23 c.s = "T";
24 c.a.x = 30;
25 assert(c.s == "T");         // `c.s` is `"T"`
26 destroy(c);
27 assert(c.dtorCount == 1);   // `c`'s destructor was called
28 assert(c.s == "S");         // `c.s` is back to its inital state, `"S"`
29 assert(c.a.dtorCount == 1); // `c.a`'s destructor was called
30 assert(c.a.x == 10);        // `c.a.x` is back to its inital state, `10`
31 
32 // check C++ classes work too!
33 extern (C++) class CPP
34 {
35     struct Agg
36     {
37         __gshared int dtorCount;
38 
39         int x = 10;
40         ~this() { dtorCount++; }
41     }
42 
43     __gshared int dtorCount;
44 
45     string s = "S";
46     Agg a;
47     ~this() { dtorCount++; }
48 }
49 
50 CPP cpp = new CPP();
51 assert(cpp.dtorCount == 0);   // destructor not yet called
52 assert(cpp.s == "S");         // initial state `cpp.s` is `"S"`
53 assert(cpp.a.dtorCount == 0); // destructor not yet called
54 assert(cpp.a.x == 10);        // initial state `cpp.a.x` is `10`
55 cpp.s = "T";
56 cpp.a.x = 30;
57 assert(cpp.s == "T");         // `cpp.s` is `"T"`
58 destroy!false(cpp);           // destroy without initialization
59 assert(cpp.dtorCount == 1);   // `cpp`'s destructor was called
60 assert(cpp.s == "T");         // `cpp.s` is not initialized
61 assert(cpp.a.dtorCount == 1); // `cpp.a`'s destructor was called
62 assert(cpp.a.x == 30);        // `cpp.a.x` is not initialized
63 destroy(cpp);
64 assert(cpp.dtorCount == 2);   // `cpp`'s destructor was called again
65 assert(cpp.s == "S");         // `cpp.s` is back to its inital state, `"S"`
66 assert(cpp.a.dtorCount == 2); // `cpp.a`'s destructor was called again
67 assert(cpp.a.x == 10);        // `cpp.a.x` is back to its inital state, `10`

Value type demonstration

int i;
assert(i == 0);           // `i`'s initial state is `0`
i = 1;
assert(i == 1);           // `i` changed to `1`
destroy!false(i);
assert(i == 1);           // `i` was not initialized
destroy(i);
assert(i == 0);           // `i` is back to its initial state `0`

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