[fitsbits] 64-bit integers

[Thierry Forveille]

Mark Calabretta writes:
 > I support the proposal, though with one reservation: how will cfitsio
 > (or your favourite FITS reader) load a BITPIX=64 image onto a 32-bit
 > computer?  Are we assuming the availability of "long long int" in C
 > (as is gcc), INTEGER*8 (or whatever it is) in FORTRAN, and similarly
 > in other languages?  Will coercing these values to double precision be
 > considered acceptable if 64-bit integers are not available?
 > 
The BITPIX=64 part of the proposal is indeed a bit less obvious than the
rest. It seems a logical thing to do for consistency, but offhand I 
cannot think of an application that would need 64-bit integers in an 
image (as opposed to the very clear need for 64-bit time ticks and 
pointers in tables). Is there anything around that will make use of 
that capability in the foreseeable future? And if not, should we
nonetheless include it on the basis of low implementation cost
(specially three years down the road, when all our laptops will be
64-bit ;-)), or not?