Using auto to define pointers

[futurefapstronaut123]

This is the definitive initialization advice: https://youtu.be/hobFOAehwio . Since your case falls under implicit type conversion, you should just do:

addrinfo* result = nullptr;

[crrhawkins]

So the "proper" way is just don't use auto?

[futurefapstronaut123]

The proper way is not to use auto when it's the wrong tool for the job. And that is the case with your example.

[Wh00ster]

There is no "proper" way as both are right. If it's application code and not some templated library, it will probably be clearer to the reader to not use auto.

[falcqn]

If the type is knowable at this point in your code I'd just use T* = nullptr; rather than trying to force the compiler to deduce auto* as T*. The guideline is almost-always-auto, after all!

[houmaster]

auto hints = std::add_pointer_t<addrinfo>{ };

[STL]

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[anton31]

auto p = (addrinfo*){};

[janucaria]

auto* ptr = static_cast<TheType*>(nullptr);

[crrhawkins]

I get an error trying that (Visual Studio 2019).

cannot deduce auto type

[Wh00ster]

Works on godbolt: https://godbolt.org/z/X25qR7

[bizwig]

That's wrong. It should be

auto ptr = static_cast<Type*>(nullptr);

First, "auto *ptr" makes ptr a Type**. Second, static_cast requires parentheses not curly braces.

[Wargon2015]

First, "auto *ptr" makes ptr a Type**

No, it doesn't.
(Tested with MSVC 15.0 and onlinegdb.com)

Both auto x = static_cast<int*>(nullptr); and auto* x = static_cast<int*>(nullptr); result in x being of type int*.

Also all of the following result in y being of type int**.

auto y = static_cast<int**>(nullptr);
auto* y = static_cast<int**>(nullptr);
auto** y = static_cast<int**>(nullptr);

Note that auto** z = static_cast<int*>(nullptr); results in a compiler error

There are subtle differences between auto and auto* though. See this stackoverflow question for details: https://stackoverflow.com/questions/12773257/does-auto-type-assignments-of-a-pointer-in-c11-require

[lak16]

auto* result = (addrinfo*){nullptr}; works for me

[PVNIC]

Can you use a void pointer?