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API Documentation

version 2.082.0

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Function object.destroy

Destroys the given object and sets it back to its 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.

void destroy(T) (
  ref T obj
)
if (is(T == struct));

void destroy(T) (
  T obj
)
if (is(T == class));

void destroy(T) (
  T obj
)
if (is(T == interface));

void destroy(T, U, ulong n) (
  ref T obj
)
if (!is(T == struct));

void destroy(T) (
  ref T obj
)
if (!is(T == struct) && !is(T == interface) && !is(T == class) && !_isStaticArray!T);

Example

Reference type demonstration 

class C
{
    struct Agg
    {
        static int dtorCount;

        int x = 10;
        ~this() { dtorCount++; }
    }

    static int dtorCount;

    string s = "S";
    Agg a;
    ~this() { dtorCount++; }
}

C c = new C();
assert(c.dtorCount == 0);   // destructor not yet called
assert(c.s == "S");         // initial state `c.s` is `"S"`
assert(c.a.dtorCount == 0); // destructor not yet called
assert(c.a.x == 10);        // initial state `c.a.x` is `10`
c.s = "T";
c.a.x = 30;
assert(c.s == "T");         // `c.s` is `"T"`
destroy(c);
assert(c.dtorCount == 1);   // `c`'s destructor was called
assert(c.s == "S");         // `c.s` is back to its inital state, `"S"`
assert(c.a.dtorCount == 1); // `c.a`'s destructor was called
assert(c.a.x == 10);        // `c.a.x` is back to its inital state, `10`

// check C++ classes work too!
extern (C++) class CPP
{
    struct Agg
    {
        __gshared int dtorCount;

        int x = 10;
        ~this() { dtorCount++; }
    }

    __gshared int dtorCount;

    string s = "S";
    Agg a;
    ~this() { dtorCount++; }
}

CPP cpp = new CPP();
assert(cpp.dtorCount == 0);   // destructor not yet called
assert(cpp.s == "S");         // initial state `cpp.s` is `"S"`
assert(cpp.a.dtorCount == 0); // destructor not yet called
assert(cpp.a.x == 10);        // initial state `cpp.a.x` is `10`
cpp.s = "T";
cpp.a.x = 30;
assert(cpp.s == "T");         // `cpp.s` is `"T"`
destroy(cpp);
assert(cpp.dtorCount == 1);   // `cpp`'s destructor was called
assert(cpp.s == "S");         // `cpp.s` is back to its inital state, `"S"`
assert(cpp.a.dtorCount == 1); // `cpp.a`'s destructor was called
assert(cpp.a.x == 10);        // `cpp.a.x` is back to its inital state, `10`

Example

Value type demonstration 

int i;
assert(i == 0);           // `i`'s initial state is `0`
i = 1;
assert(i == 1);           // `i` changed to `1`
destroy(i);
assert(i == 0);           // `i` is back to its initial state `0`

Authors

Walter Bright, Sean Kelly

License

Boost License 1.0.