2 An example of undefined behavior is the behavior on integer overflow.
c99:
3.4.3
1 undefined behavior
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3 EXAMPLE An example of undefined behavior is the behavior on integer overflow.
c++98、2003
5 Expressions [expr]
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5 If during the evaluation of an expression, the result is not mathematically defined or not in the range of representable
values for its type, the behavior is undefined, unless such an expression is a constant expression (5.19), in which case the program is ill-formed.