2004.04.26 11:06 "Re: [Tiff] Large TIFF files", by Rob van den Tillaart
It is not possible to select allways in advance the right mode, as a user can decide to enlarge a bitmap to > 4GB. When 32 bit mode was chosen and there is a sudden runtime switch to 64bit mode I can imagine quite some difficulties.
=> So the library must work internally in 64 bit mode.
The premis, I agree with, but my conclusion is => so the library user must specify if it wants to write a 32bit or 64bit file in advance, using a flag in the primary TIFFOpen call.
Your earlier question is also valid for the library user (programmer): It does not always know in advance if it needs 32/64 bit. Or you get the scenario in which the programmer selects 32 bit and at some time an Exception/error will occur as data doesn't fit in 4GB. This could imply that all work on the bitmap(s) has to be redone, now in 64bit mode, which takes a lot of time. (Worst case you lose customers). I expect that after such experience most programmers will select 64 bit, or there must be a hard requirement for 32 bit only.