两个结构初始化之间的区别

Question

Struct下面两个初始化有什么区别？

Car ford = {
    .name = "Ford F-150",
    .price = 25000
};

并且：

Car dodge = (Car) {
    .name = "Ram",
    .price = 1000
};

从Compiler Explorer开始，看起来两者生成的代码相同：

(StructName) 在结构前面有什么作用？在进行复杂的初始化时似乎有必要，例如：

CarPtr mazda = & (Car) {
    .name = "Mazda",
    .price = 20000
};

也与的两个答案有关。

Answer 1

在此声明中

Car dodge = (Car) {
    .name = "Ram",
    .price = 1000
};

创建了两个 Car 类型的对象。第一个是未命名的复合文字

(Car) {
    .name = "Ram",
    .price = 1000
}

用于初始化另一个命名对象闪避。

来自 C 标准（6.5.2.5 复合文字）

3 A postfix expression that consists of a parenthesized type name followed by a braceenclosed list of initializers is a compound literal. It provides an unnamed object whose value is given by the initializer list.

其实类似于下面的声明

Car ford = {
    .name = "Ford F-150",
    .price = 25000
};

Car dodge = ford;

不同的是，在上一个例子中我们又创建了一个命名对象。

来自C标准（6.7.9初始化）

13 The initializer for a structure or union object that has automatic storage duration shall be either an initializer list as described below, or a single expression that has compatible structure or union type. In the latter case, the initial value of the object, including unnamed members, is that of the expression.

两个结构初始化之间的区别

Difference between two struct initializations

c

struct

initialization

compound-literals