2023.04.12 15:14 "[Tiff] TIffWriteDirectory() causes problems", by David C. Partridge

2023.04.13 15:24 "Re: [Tiff] TIffWriteDirectory() causes problems", by Olivier Paquet

It isn't the same. As far as I can tell, multiple TIFFCheckpointDirectory calls will reuse the same space in the file but the final directory write will still allocate new space at the end. I'm not fully familiar with the write code but I suspect there are assumptions made, like you shouldn't add tags between checkpoints but you're allowed to before the final write. Or, just as likely, it just happened this way when checkpointing was implemented. I don't think it is a widely used feature and the wasted space may not have bothered anyone. I certainly never noticed it before.

Olivier