我的编译器是最新的VC ++ 2013 RC。
My compiler is the latest VC++ 2013 RC.
int f(bool b) { return {}; // OK return b ? 1 : { }; // C2059: syntax error : '{' return b ? 1 : {0}; // C2059: syntax error : '{' return b ? {1} : {0}; // C2059: syntax error : '{' }为什么可以支撑初始化-列表不能在三元运算符中使用?
Why can braced-init-list not be used in ternary operator?
此行为是C ++标准定义的格式错误还是VC ++编译器的错误? strong>
Is this behavior defined as ill-formed by the C++ standard, or just a bug of the VC++ compiler?
推荐答案好吧,这是标准关于braced-init-list(8.5.3.1)的内容:
Well, here's what the standard says about the braced-init-list (8.5.3.1):
可以使用列表初始化
List-initialization can be used
- 作为变量定义中的初始化程序(8.5)
- 作为新表达式中的初始化程序(5.3.4)
- 在return语句中( 6.6.3)
- 作为函数参数(5.2.2)
- 作为下标(5.2.1)
- 作为构造函数调用的参数(8.5,5.2.3)
- 作为非静态数据成员的初始化程序(9.2)
- 在内存初始化器(12.6.2)
- 在任务右侧(5.17)
- as the initializer in a variable definition (8.5)
- as the initializer in a new expression (5.3.4)
- in a return statement (6.6.3)
- as a function argument (5.2.2)
- as a subscript (5.2.1)
- as an argument to a constructor invocation (8.5, 5.2.3)
- as an initializer for a non-static data member (9.2)
- in a mem-initializer (12.6.2)
- on the right-hand side of an assignment (5.17)
由于这里没有提到条件运算符,所以我猜您的编译器是正确的。还要注意,条件运算符期望:(5.16)的两面都有表达式,据我所知,花括号初始化器不是表达式。
Since this doesn't mention the conditional operator, I guess your compiler is right. Also note that the conditional operator expects expressions on the both sides of : (5.16), and as far as I understand, a brace-initializer is not an expression.
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为什么不能在三元运算符中使用braced
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