[Rucadi]

auto has a good perk, it prevents uninitialized values (Which is a source of bugs).

For example:

auto a;

will always fail to compile not matter what flags.

int a;

is valid.

Also it prevents implicit type conversions, what you get as type on auto is the type you put at the right.

That's good.

[feelamee]

uninitialized values are not the source of bugs. This is a good way to find logic errors in code (e.g. using sanitizer)

[jb1991]

"bug" can refer to many categories of problems, including logic errors. I've certainly seen uninitialized variables be a source of bugs. Stackoverflow for example is full of discussions about debugging problems caused by uninitialized variables, and the word "bug" is very often used in those contexts.

What do you mean it is not a source of bugs?

[1718627440]

> What do you mean it is not a source of bugs?

I think what they mean, and what I also think is that the bug does not come from the existence of uninitialized variables. It comes from the USE of uninitialized variables. Making the variables initialized does not make the bug go away, at most it silences it. Making the program invalid instead (which is what UB fundamentally is) is way more helpful for making programs have less bugs. That the compiler still emits a program is a defect, although an unfixable one.

As to my knowledge C (and derivatives like C++) is the only common language where the question "Is this a program?" has false positives. It is certainly an interesting choice.

[feelamee]

I mean that bug is *not in* uninitialized variable - bug in program logic. E.g. one of code pathes don't initialize variable.

So, I see uninitialized variables as a good way to find such logic errors. And, therefore, advice to always initialize variable - bad practice.

Of course if you already have a good value to initialize variable - do it. But if you have no - better leave it uninitialized.

Moreover - this will not cause safety issues in production builds because you can use `-ftrivial-auto-var-init` to initialize automatic variables to e.g. zeroes (`-fhardened` will do this too)

[jb1991]

This is indeed exactly correct. Probably on its own this is the most important reason for most people to use it, as I think most of the millions of C++ developers in the world (and yes there are apparently millions) are not messing with compiler flags to get the checks that probably should be there by default anyway. The keyword auto gives you that.