boost::algorithm::all_of works strangely with TriBool about boost HOT 4 CLOSED

Then don't return TriBool from your predicate. all_of expects boolean results.

from boost.

Consider the following code:

   if ( isOdd(5)) std::cout << "is odd!\n";
   if (!isOdd(5)) std::cout << "is not odd!\n";

If you put that into your test program, you'll find that neither one of them is printed.
That matches the behavior of all_of as well.

from boost.

all_of applies the predicate to every element in the sequence, and if any of them fail (i.e, the predicate returns something that is "not true"), the it returns false.
Otherwise, it returns true.
That's what is happening here.

from boost.

"(i.e, the predicate returns something that is "not true"), the it returns false."

The predicate returns boost::logic::indeterminate which is not true, then it returns true

If this behavior is okay, I am also okay with that but I found it in some sense non-intuitive and waste time debugging.

from boost.