[s3graham]

As you surely know if you're quoting the standard, it depends on which standard!

[tedunangst]

Quote a different standard.

[gpderetta]

I believe that since C23 foo() is now a nullary function. As this is the last approved standard and it supersedes all previous standards, it is technically correct to say that de-jure this is what the (unqualified) C standard mandates.

Of course de-facto things are more nunanced.

[el_pollo_diablo]

C23 does not change anything in this situation, because we are talking about the definition of main(), not a forward declaration. More details here:

https://news.ycombinator.com/item?id=38729278#38732366