Any attributes on a forward declaration should be less than the attributes on the definition or, at most, equal to them.

前向声明上的任何特性都应小于定义上的特性，或至多等于这些特性。

youdao

Any attributes on a forward declaration should be less than the attributes on the definition or, at most, equal to them.

前向声明上的任何特性都应小于定义上的特性，或至多等于这些特性。

youdao