c – “std :: make_shared()”值是否初始化我的POD？

std :: make_shared< POD>()值初始化我的POD？

如果是,这是否符合标准？

如果没有(我怀疑),有没有办法呢？我猜std :: make_shared< POD>(POD())会做,但是我应该做什么？

解决方法

是的,这是值得注意的,这是由标准保证的：

§20.7.2.2.6,2:(关于make_shared)

Effects: Allocates memory suitable for an object of type T and constructs an object in that memory via the placement new expression ::new (pv) T(std::forward<Args>(args)...).

和§5.3.4,15：

A new-expression that creates an object of type T initializes that object as follows:
— If the new-initializer is omitted,the object is default-initialized (8.5); if no initialization is performed,the object has indeterminate value.
— Otherwise,the new-initializer is interpreted according to the initialization rules of 8.5 for directinitialization.

因此,它将直接初始化为新的POD().

§8.5,16：

The semantics of initializers are as follows. […]
— If the initializer is (),the object is value-initialized.

原文地址：https://www.jb51.cc/c/112001.html