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1323 A constant expression can be evaluated during translation rather than runtime, and accordingly may be used in any place that a constant may be.
1324 Constant expressions shall not contain assignment, increment, decrement, function-call, or comma operators, except when they are contained within a subexpression that is not evaluated.96)
1325 Each constant expression shall evaluate to a constant that is in the range of representable values for its type.
1326 An expression that evaluates to a constant is required in several contexts.
1327 If a floating expression is evaluated in the translation environment, the arithmetic precision and range shall be at least as great as if the expression were being evaluated in the execution environment.
An integer constant expression97) shall have
integer type and shall only have operands that are integer constants,
enumeration constants, character constants,
Cast operators in an integer constant expression shall only convert
arithmetic types to integer types, except as part of an operand to
1330 More latitude is permitted for constant expressions in initializers.
1331 Such a constant expression shall be, or evaluate to, one of the following:
1332 an arithmetic constant expression,
1333 a null pointer constant,
96) The operand of a
97) An integer constant expression is used to specify the size of a
bit-field member of a structure, the value of an enumeration
constant, the size of an array, or the value of a
1336 Further constraints that apply to the integer constant expressions used in conditional-inclusion preprocessing directives are discussed in 6.10.1.
1337 an address constant, or
1338 an address constant for an object type plus or minus an integer constant expression.
An arithmetic constant expression shall have arithmetic type
and shall only have operands that are integer constants, floating
constants, enumeration constants, character constants, and
Cast operators in an arithmetic constant expression shall only
convert arithmetic types to arithmetic types, except as part of an
operand to a
1341 An address constant is a null pointer, a pointer to an lvalue designating an object of static storage duration, or a pointer to a function designator;
it shall be created explicitly using the unary
1344 An implementation may accept other forms of constant expressions.
1345 The semantic rules for the evaluation of a constant expression are the same as for nonconstant expressions.98)
1346 Forward references: array declarators (18.104.22.168), initialization (6.7.8).
1347 98) Thus, in the following initialization,
static int i = 2 || 1 / 0;
the expression is a valid integer constant expression with value one.
Created at: 2008-01-30 02:39:43
The text from WG14/N1256 is copyright © ISO
Created at: 2008-01-30 02:39:43 The text from WG14/N1256 is copyright © ISO