2008.08.23 15:54 "Re: [Tiff] creating sparse files......", by Bob Friesenhahn

For example, Apple OS-X's HFS+ does not support holes.

Weird. So, will my suggested code fail? No.

OS-X's HFS+ will simply consume the space with zeros.

Windows FAT type filesystems (still very much in use in millions of systems/devices) do not support holes.

Correct. But will my code fail? No. It does skip the copying of "zeroes" from userspace into the kernel. Wether this will in fact increase or decrease perfomance when all things are added up, I don't know.

The code may very well fail.

It is likely that you don't know that the posix specifications are pretty clear about this.

If I program

        main (int argc, char **argv)
        {
                int a;
                int b;
                a = 3;
                b = 5;
                printf ("%d\n", a+b);
        }

the output should be "8". This is because I used standard features of a standard programming language. Opening and writing files goes a bit

You are communicating with someone who has used and programmed "unix" for twenty years now. The above was not called for.

Bob
======================================
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/