CODEWITHSUNDEEP
c++
tz39R
tz39R

Reputation: 75

Is it possible to "return a return statement"?

Is it possible to return a return statement in C++ or to do something with similar functionality?

This would be handy if, for example, there are several functions in the code which take a pointer as an input and each of them checks if the pointer is a nullptr or not. If it is a nullptr the function should stop whatever it is doing and return 0, or whatever is appropriate for its type.

Let inputPtr be an int* given to a function which returns an int. Instead of writing things like

    ...
    if(inputPtr == nullptr) {
        return 0;
    }
    ...

every time, it would be cool to just have

    ...
    checkNull(inputPtr);
    ...

or something similar. In this example it's not too bad of course, but imagine a more elaborate testing function.

Conceptually, this seems to be quite weird. But usually there is a way to prevent repetition.

Upvotes: 4

Views: 196

Answers (3)

NewMe
NewMe

Reputation: 162

I think there are three options basically:

  1. Macros
  2. Exceptions
  3. gsl::not_null

here you have good post about it. https://www.bfilipek.com/2017/10/notnull.html (of course it is not perfect solution but it may save you some time:))

Upvotes: 1

Clifford
Clifford

Reputation: 93496

No, it is not possible, and hiding control flow might be considered a bad idea in any event. If you have to write the checking function, it is simple enough to make that return a Boolean then:

if(checkNull(inputPtr)) return 0 ;

Upvotes: 7

SergeyA
SergeyA

Reputation: 62583

Unfortunately, this is one the very few things which can only be solved with macro in C++.

That is, you really can't stand extra if in the code and you have a wide contract, which allows for nullptrs to be given as arguments.

I personally would not use macro and would just use clear if statements.

Upvotes: 1

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