c++ - 结构变量成员后的花括号是什么意思？

Question

在一些维护(Valgrind'ing)期间，我遇到了这个代码:

#pragma pack(push, 1)
struct somename
{
  uint16_t a{};
  uint16_t b{};
  uint32_t  c{};
};
#pragma pack(pop)

我希望 {}告诉编译器始终将值初始化为 0(使用 new 或使用堆栈变量分配时)，但我找不到任何示例或文档。我在这个假设中正确吗？如果不:

花括号有什么作用 {}后一个struct成员变量是什么意思？

Answer 1

这是 default member initializer (从 C++11 开始)。
(强调我的)

Through a default member initializer, which is a brace or equals initializer included in the member declaration and is used if the member is omitted from the member initializer list of a constructor.

If a member has a default member initializer and also appears in the member initialization list in a constructor, the default member initializer is ignored for that constructor.

作为效果，数据成员 a , b和 c是 value-initialized ( zero-initialized 对于内置类型)到 0 .