> I believe you are looking for ENOSYS.
>
> As one of the things I am doing in my ever-expanding-in-scope
> CD include patch (see http://www.inconnect.com/~andersen/files)
> is to return ENOSYS for non-implemented functions instead of
> EINVAL.
Hmm, not exactly. "not implemented" (in the driver) is a bit different
from "drive can't do".
> Grep /usr/include/asm/errno.h some time and you will
> have your eyes opened to all the official things that can go wrong.
I *did* check this. Is there some standard paper which tells what the
error codes mean? Lets take ENODEV as example. linux errno.h says:
#define ENODEV 19 /* No such device */
According to some other mail I got glibc 2.1 says:
ENODEV = "Operation not supported by device"
One of them is completely wrong...
glibc is newer and probably checked against posix, so I think I'll take
ENODEV.
Gerd