Do I get a performance issue, if i do not care about a return value

Question

Introduction: I got a function doing some work and returning a bool. The bool should be false, if some error occured. So I could use the bool, if I want to check for errors. But what, if I am completely sure (I know, you can never be completely sure, but maybe you understand what I mean) that there will be no error in this part or you just don't care if there is because it has no influence.

Question: Will there occure some memory leak or other performance issue if I just not 'catch' the returned bool?

minimum Codeexampe:

bool my_func(/*some variables*/)
{
    if(/*error-condition*/)
    {
        //do something
        return false;
    }
    else if(/*other error-condition*/)
    {
        //do something
        return false;
    }
    return true;
}


int main(void)
{
    my_func(/*variables*/);
    return 0;
}

Comment: that will not return any compiling or runtime errors or unhandled exceptions

Answer 1

You can safely ignore the return value of a function if it is not a pointer to memory that was allocated from within the function and not freed within that function.

Answer 2

In C++ memory can only leak for objects with dynamic storage duration, that is, objects allocated with new or std::malloc (cmp. C++11 3.7.4/1)

The bool in your function will be a temporary, or in other words, it has automatic storage duration (cmp. C++11 3.7.3/1), so it is perfectly fine to ignore that.

Answer 3

Function return values can always be ignored unless they tell you information about resources that a function has consumed and not released; e.g.

1) A pointer or a structure containing pointers to memory allocated by the function

2) A pointer or a structure containing pointers to files / stream buffers opened by the function

You should always check the function documentation before choosing to ignore a return value.

Answer 4

No, there will be no performance loss or memory leak. However, in general exceptions are the proper way of handling errors in C++.

Answer 5

No, it is a void statement, the bool is discarded

Answer 6

You can feel free to ignore it as the return value just doesn't gets used. It is just a void statement this would be at all the same as writing 2; or identifiername; In your code.

It would get invoked, but as you aren't storing the value, nothing else will happen.