重载<< operator C ++ - 指向类的指针 [英] Overloading << operator C++ - Pointer to Class

问题描述

class logger {
 ....
};

logger& operator<<(logger& log, const std::string& str)
{
    cout << "My Log: " << str << endl;
    return log;
}

logger log;
log << "Lexicon Starting";

工作正常，但我想使用指向类实例的指针。即

Works fine, but i would like to use a pointer to a class instance instead. i.e.

logger * log = new log();
log << "Lexicon Starting";

这可能吗？如果是这样，什么是语法？感谢

Is this possible? If so what is the syntax? Thanks

编辑：编译器错误是

error: invalid operands of types 'logger*' and 'const char [17]' to binary 'operator<<'

推荐答案

你必须将指针解引用到你的logger对象，显然检查它是不是0.这样的东西应该做的工作：

You'd have to dereference the pointer to your logger object and obviously check if it's not 0. Something like this should do the job:

  log && ((*log) << "Lexicon starting")

一般来说，我会避免引用对象像一个记录器（你通常无条件地期望存在）通过指针，由于你用指针得到的不确定性， AKA有没有对象？

As a general aside, I would shy away from referencing objects like a logger (which you normally unconditionally expect to be present) via a pointer due to the uncertainty you get with a pointer, AKA is there an object or not?

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