On Tue, 16 Feb 2021 10:26:52 +0900 William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote: > On Sun, Feb 14, 2021 at 05:10:21PM +0000, Jonathan Cameron wrote: > > On Fri, 12 Feb 2021 21:13:34 +0900 > > William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote: > > > > > ERANGE is a semantically better error code to return when an argument > > > value falls outside the supported limit range of a device. > > > > #define ERANGE 34 /* Math result not representable */ > > > > Not generally applicable to a parameter being out of range > > despite the name. > > #define EINVAL 22 /* Invalid argument */ > > Is probably closer to what we want to describe here. > > > > Jonathan > > The comment for ERANGE in error-base.h may be terse to a fault. I > believe there's a connotation here provided by ERANGE that is absent > from EINVAL: primarily that the device buffer is incapable of supporting > the desired value (i.e. there is a hardware limitation). > > This is why strtoul() returns ERANGE if the correct value is outside the > range of representable values: the result of the operation is valid in > theory (it would be an unsigned integer), but it cannot be returned to > the user due to a limitation of the hardware to support that value (e.g. > 32-bit registers) [1]. > > The changes in this patch follow the same logic: these are arguments > that are valid in theory (e.g. they are unsigned integers), but the > underlying devices are incapable of processing such a value (e.g. the > 104-QUAD-8 can only handle 24-bit values). > > [1] https://stackoverflow.com/a/34981398/1806289 Its a bit of a stretch, but I can't claim to feel that strongly about this. Jonathan > > William Breathitt Gray
