带&&运算符的C ++函数返回

Question

I'm looking through a library, and I see this function:

bool CCAPI::IsConnected() const
{
    int state;
    int res = CCAPIGetConnectionStatus(&state);
    return (res == CCAPI_OK) && state;
}

Specifically, what does this last line mean? It looks to me like it's returning two variables as it's using the && operator. So what's going on here?

Answer 1

It is going to return a single bool , like the function says it will.

The operator && is logical AND , so if res == CCAPI_OK and state != 0 then it will return true . In this case state is being implicitly converted to bool for the && operation.

Answer 2

Operator && is Logical AND , could be written as and too.

The logical operators apply logic functions (NOT, AND, and inclusive OR) to boolean arguments (or types contextually-convertible to bool), with a boolean result.

So the last statement will return the operation result with type bool .