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Re: RFD: C pointer conversions that differ in unsignedness
On Dec 5, 2005, at 9:53 AM, schopper-gcc@bfw-online.de wrote:
Oh right, what I really meant was 'char' instead of 'long'.
In fact I just took the type from the referenced article. Sorry for
that.
So am I right that the compiler should distinguish between char,
signed char
and unsigned char in the proposed way?
Good question. I don't believe so:
[#5] Each of the comma-separated sets designates the same
type, except that for bit-fields, it is implementation-
defined whether the specifier int designates the same type
as signed int or the same type as unsigned int.
[ note, I have a feeling they meant char, not int, I suspect someone
might be able to provide a pointer to a DR for this. ]
[#14] The type char, the signed and unsigned integer types,
and the floating types are collectively called the basic
types. Even if the implementation defines two or more basic
types to have the same representation, they are nevertheless
different types.29)
[#15] The three types char, signed char, and unsigned char
are collectively called the character types. The
implementation shall define char to have the same range,
representation, and behavior as either signed char or
unsigned char.30)
30)CHAR_MIN, defined in <limits.h>, will have one of the
values 0 or SCHAR_MIN, and this can be used to
distinguish the two options. Irrespective of the choice
made, char is a separate type from the other two and is
not compatible with either.
Did you find wording in the standard that mandates no diagnostic on
the first three?