2008.08.23 16:23 "Re: [Tiff] creating sparse files......", by Rogier Wolff

On Sat, Aug 23, 2008 at 11:07:20AM -0500, Bob Friesenhahn wrote:

Ehh. You do have to take into account that this was written in the module "tif_unix.c" or something like that. Wether this is active on Microsof operating systems as well, I don't know. Sounds like it should not be....

Probably "tif_unix.c" should really be called "tif_posix.c". It does actually work under Windows using Window's underscore-prefixed POSIX

Well if it claims Posix compatibility, and then doesn't conform to the posix specifications, then I'd claim "it doesn't work".

API equivalents. If you use the 'configure' based build under Cygwin or MinGW, then "tif_unix.c" will be used and "tif_unix.c" may be selected under Windows in other situations as well.

The Windows API documentation does not specify that intermediate bytes are automatically initialized to zero if you seek past the end of the file and write some data. The only WIN32 interface which is documented to extend the file while initializing with zero is chsize(), which is unfortunately limited to only 2GB due to the range of off_t under WIN32.

Which means that apparently the "ftruncate" call needs to be translated into chsize() by the library that pretends to provide posix compatibility on windows.

http://www.opengroup.org/onlinepubs/009695399/functions/ftruncate.html

If my suggestion doesn't work on windows, then I'm ok with #ifndef WINDOWS around my code. You (or someone else) was suggesting putting in deviceIoctl's... Well that's not portable and would also need to be surrounded by some ifdefs.

Oh. You mentioned: "if it's YOUR application that becomes slower". Indeed, I'd feel bad about it. However, I'm used to this happening all the time. Every time I upgrade, things are becoming more bloated and slower. This doesn't only happen in "windows-land".

My first Linux machine had a whopping 8M bytes of memory. I had that expanded to 20, a year later. I remember booting the machine, and thinking it had crashed with the HDD led turned on when I accidentally booted it one day with only 4M installed.... It popped up the default X root screen when I was moving my arm towards the reset button....

        Roger.

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