Does the unary + operator have any practical use?

Question

Was the unary + operator only included for symmetry with the unary - operator, or does it find some practical use in C++ code?

Searching h

Answer 1

Among other things, + converts lambdas to function pointers. Normally the conversion happens automatically, but sometimes it doesn't.

For example, this doesn't compile:

std::array arr{
    [](int x){return x*x;},
    [](int x){return x*x*x;},
};

You could make it work by specifying the function pointer type as the std::array template parameter, or you could just do this:

std::array arr{
    +[](int x){return x*x;},
    +[](int x){return x*x*x;},
};