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Function std.algorithm.mutation.move
Moves sourcetargetcopy.
Prototypes
void move(T)( T source, T target ); T move(T)( T source );
Parameters
| Name | Description |
|---|---|
| source | Data to copy. If a destructor or postblit is defined, it is reset
to its .init value after it is moved into target. Note that data
with internal pointers that point to itself cannot be moved, and will
trigger an assertion failure. |
| target | Where to copy into. The destructor, if any, is invoked before the
copy is performed. |
Example
Object obj1 = new Object; Object obj2 = obj1; Object obj3; move(obj2, obj3); assert(obj3 is obj1);
Example
// Structs without destructors are simply copied
struct S1
{
int a = 1;
int b = 2;
}
S1 s11 = { 10, 11 };
S1 s12;
move(s11, s12);
assert(s11.a == 10 && s11.b == 11 &&
s12.a == 10 && s12.b == 11);
// But structs with destructors or postblits are reset to their .init value
// after copying to the target.
struct S2
{
int a = 1;
int b = 2;
~this() pure nothrow @safe @nogc { }
}
S2 s21 = { 3, 4 };
S2 s22;
move(s21, s22);
assert(s21.a == 1 && s21.b == 2 &&
s22.a == 3 && s22.b == 4);
Example
struct S
{
@disable this(this);
~this() pure nothrow @safe @nogc {}
}
S s1;
S s2 = move(s1);
Example
static struct Foo
{
pure nothrow @nogc:
this(int* ptr) { _ptr = ptr; }
~this() { if (_ptr) ++*_ptr; }
int* _ptr;
}
int val;
Foo foo1 = void; // uninitialized
auto foo2 = Foo(&val); // initialized
// Using move(foo2, foo1) has an undefined effect because it destroys the uninitialized foo1.
// MoveEmplace directly overwrites foo1 without destroying or initializing it first.
assert(foo2._ptr is &val);
moveEmplace(foo2, foo1);
assert(foo1._ptr is &val && foo2._ptr is null);