[nealabq]

I don't mean to be that guy, but for "functional" programmers a print statement has "side effects".

But your meaning is clear. In an assert expression, don't call functions that might change the program/database state. Be as "const" as possible.

[toxik]

Not just for functional programmers. Prints and other I/O operations absolutely are side effects. That's not running counter to the point being made. Print in an assert and NDEBUG takes away that behavior.

[nealabq]

You're right of course. I was thinking specifically of printing log/debug statements in the assert(..), but that usually only happens if the assert(..) fails and exits, and in that case the "no side effects" rule no longer matters.