Re: ENOIOCTLCMD?

[Alan Cox]

> Can somebody explain the use of ENOIOCTLCMD? There are order of 170 
> uses in the kernel, but I don't see any guidelines for that use (nor 
> what prevents it from being seen by user programs).

It should never be seen by apps. If it can be then it is wrong code.
Basically you use it in things like

	int err = dev->ioctlfunc(dev, op, arg);
	if( err != -ENOIOCTLCMD)
		return err;

	/* Driver specific code does not support this ioctl */

	switch(op)
	{

			...
		default:
			return -ENOTTY;
	}

Its a way of passing back 'you handle it'