[Nut-upsdev] gcc4 compiler warnings

[Arjen de Korte]

> On Thu, 9 Feb 2006, Charles Lepple wrote:
>
>> On 2/9/06, Arjen de Korte <nut+devel at de-korte.org> wrote:
>>> This is due to the fact that some drivers need to pass character values
>>> between 0x80 and 0xFF to or from the drivers, but the serial functions
>>> use
>>> signed chars. Unless some drivers use negative values, my preference
>>> would
>>> be to fix/create serial functions (to use unsigned chars), rather than
>>> to
>>> convert the characters between 0x80 and 0xFF to negative numbers.
>>> Especially where status bits are used, listing a hex value is more
>>> readable then.
>>
>> I tend to agree with Arjen on this one - most drivers will be treating
>> characters as unsigned, since the majority of the values being
>> returned are unsigned.
>
> Indeed. It didn't even occur to me that the serial functions might use
> signed char for input/output. I'm all for fixing this the proposed
> (==right) way.

In that case, how are we going to implement this? Modify the existing
drivers to use unsigned char for all communication with the UPS or create
new ones? Be aware that some drivers use string operations on the results
received from the UPS (strlen or strcmp for instance) and will require
typecasting there (char *). Otherwise we're in for a lot more compiler
warnings from string operations.

Nevertheless, I would prefer typecasting (unsigned char *) to (char *)
over the reverse, since string operations are usually performed on (7 bit)
ASCII text only, where there is no real difference between using unsigned
and signed chars.

Regards, Arjen