int foo = foo的标准引用 [英] Standard reference for int foo = foo

问题描述

int foo = foo; 编译。
C ++标准的哪一部分允许这个？

int foo = foo; compiles. Which part of the C++ standard allows this?

推荐答案

声明[basic.scope.pdecl]

3.3.1 Point of declaration [basic.scope.pdecl]

名称的声明点紧接在其完整的声明器（第8节）之后，在它的初始化器（如果有） / p>

The point of declaration for a name is immediately after its complete declarator (clause 8) and before its initializer (if any),

如果声明在文件范围内，行为是很好定义的。如果你在函数范围有声明，如果你使用 foo 以后[这将被初始化为一些未指定的值]行为将是未定义的。

The behaviour is well defined if the declaration is at file scope. If you have the declaration at function scope and if you use foo later on [which would be initialized to some unspecified value in that case] the behaviour would be undefined.

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