Defect Report #067

Submission Date: 03 Dec 93
Submittor: WG14
Source: Clive Feather
Question
Item 4 - definitions of types
The terms ``signed integer type,'' ``unsigned integer type,'' and ``integral type'' are defined in subclause 6.1.2.5. The C Standard also uses the terms ``integer type,'' ``signed integral type,'' and ``unsigned integral type'' without defining them. Integer-valued bitfields are also introduced in subclause 6.5.2.
  1. For each of the following types, which if any of the six categories above do they belong to?
    char
    signed char
    unsigned char
    signed short
    unsigned short
    signed int
    unsigned int
    signed long
    unsigned long
    int : N /*     i.e. bitfield of size N /*
    signed int : N
    unsigned int : N
    enumerated type
  2. For each of these categories, do the const and/or volatile qualified versions of the types belonging to the category also belong to the category?
  3. Can an implementation extension add other types defined by the C Standard to any of these six categories?
  4. Can an implementation define other types (e.g. __very long) which belong to any of these six categories?
  5. If the answer to (c) or (d), or both, is yes, can size_t and ptrdiff_t be one of these other types, or must it be a type in the above list?
Response
a) ``Signed integer type'', ``unsigned integer type'', and plain ``integer type'' are used interchangeably with ``signed integral type'', ``unsigned integral type'', and ``integral type'' in the C Standard. This observation makes it easy to categorize the types in your list.
b) Yes, see subclause 6.1.2.5.
c) No, the list in the C Standard is meant to be exhaustive. For example, float cannot be defined as an integer type.
d) No strictly conforming program could contain an instance of such a type. The treatment of such types is beyond the scope of the C Standard.
e) No, it must be a type in the list. For example, size_t cannot be defined as unsigned __int24.
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