Many thanks to Test Screen Name and Dave,
Max bookmark title length results are different between creating method.
I have following results:
Word + PDFMaker9 : 254 chars.
Writing PDFMark in PS + Distiller9+ : 373 (374?) chars.
Editing Bookmark pane with Acrobat9+ : 751 chars
It's interesting and confusing.
In fact creating CRLF in bookmark is easy.
1. Enter "abc" in bookmark pane and finish editing with <Enter>.
2. Edit the same bookmark, move cursor to end and add "def", finish editing by clicking somewhere.
This simple procedure generates "abc<crlf>def" bookmark.
My test app exporting bookmarks with CSV format was corrupted by this bookmark.
What about other control characters... tab , beep (it may be fun if possible) or something?
I have to decide whether to remove or escape them.
It is surprising ISO standard does not define them.
I'm waiting for further information.