Extra newline. (It would be better to remove it from the previous example.)

Can we not support a modifier, so %lb takes a long, %jb takes an intmax_t, etc., instead of having this ad-hoc encoding?

Fixed. The previous example has been fixed in a separate commit.

That is already supported by the code above. But you need to be able to specify bit positions from 1 to 128 now. The positions from 1 to 32 are encoded as characters from \01 to \40. So you need a way to encode the other positions. OpenBSD also uses the characters from \200 to \377 for it. If you have a different idea, I am happy to explore it.

Once this is in, I need to change clang such that it knows that you can use a length modifier (like l or j) in combination with %b. Right now it is warning that you can only use a 32-bit entity. But when you just ignore the warning, it works. Fixing clang is the next step when this change is in.

Sure. Will do this.

In case we want to support printing flags from an 128 bit integer variable (uint128_t).

When does that ever happen?

uintmax_t is 64 bits wide, so that won't work anyway.

*q++ is already is in other places in this file. So I keep it for consistency.

I don't know. Would you prefer to limit the bit number range to 1, ..., 64? Using 1,..., 128 also results in having not invalid characters.

It's fine as it is, or at least it doesn't really matter. I just found the description confusing. I don't think we will ever use 128-bit flag variables.

I see.