C ++ 0x lambda捕获的值总是const? [英] C++0x lambda capture by value always const?
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问题描述
有没有什么方法来捕获值,并使捕获的值不恒定?我有一个图书馆函子,我想捕获&调用一个非const方法,但应该是。
Is there any way to capture by value, and make the captured value non-const? I have a library functor that I would like to capture & call a method that is non-const but should be.
以下不编译,而是使用foo :: operator()const修复它。
The following doesn't compile but making foo::operator() const fixes it.
struct foo
{
bool operator () ( const bool & a )
{
return a;
}
};
int _tmain(int argc, _TCHAR* argv[])
{
foo afoo;
auto bar = [=] () -> bool
{
afoo(true);
};
return 0;
}
推荐答案
使用mutable。 >
Use mutable.
auto bar = [=] () mutable -> bool ....
如果没有可变变量,则声明lambda对象const的operator()。
Without mutable you are declaring the operator () of the lambda object const.
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