Re: Safe error numbers for User-defined return values

[Alan Cox]

> I want to define custom return values for my ioctl calls in my Kernel 
> module.  What is the recommended start value for user defined constants?  
> I notice asm/errno.h only goes up to 124 (in 2.4.12), so should I start at 
> 125 or should I start at 200 to be safe?
> 
> I probably only need 30 or so different codes.

You want to return non base errno codes in a different field and return
real errno codes by return value. If everyone simple invented private
returns for ioctl all hell would break loose