c-function-try-block和noexcept

对于以下代码

struct X
{
    int x;
    X() noexcept try : x(0)
    {
    } 
    catch(...)
    {
    }
};

Visual Studio 14 CTP发出警告

warning C4297: ‘X::X’: function assumed not to throw an exception but
does

note: __declspec(nothrow), throw(), noexcept(true), or noexcept was
specified on the function

这是对noexcept的滥用吗？还是Microsoft编译器中的错误？

解决方法:

Or is it a bug in Microsoft compiler?

不完全的.

像这样的所谓的function-try-block不能阻止异常进入外部.考虑到对象永远不会完全构造,因为构造函数无法完成执行. catch块必须抛出其他东西,否则当前异常将被重新抛出([except.handle] / 15)：

The currently handled exception is rethrown if control reaches the end
of a handler of the function-try-block of a constructor or
destructor.

因此,编译器推断出构造函数确实可以抛出异常.

struct X
{
    int x;
    X() noexcept : x(0)
    {
        try
        {
            // Code that may actually throw
        }
        catch(...)
        {
        }
    } 
};

应该在没有警告的情况下进行编译.

标签：noexcept,c,c11,c14,visual-c
来源： https://codeday.me/bug/20191010/1887695.html