[developer] Re: SEEK_DATA should fail at EOF

[Bill Sommerfeld]

On 2/14/25 23:42, Cedric Blancher wrote:
> cc: illumos-dev@ list. How does Solaris or Illumos behave? SUN/Solaris
> invented SEEK_DATA/SEEK_HOLE, so this should be - aside from looking
> at the OpenGroup/POSIX specs - the reference implementation.

Thanks for asking.

On Illumos, SEEK_DATA fails with ENXIO at EOF, and more generally fails 
with ENXIO if there are no non-hole regions in the file after the passed 
offset -- a file may end in a hole, so you may also get ENXIO for 
offsets less than the file's length.

The lseek manpage says:

...
ERRORS
        The lseek() function will fail if:
...
        ENXIO
            For SEEK_DATA, there are no more data regions past the
            supplied offset.  For SEEK_HOLE, there are no more holes
            past the supplied offset.

						- Bill