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The C Standard, 6.5.7 paragraph 4 [ISO/IEC 9899:2011], states
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In almost every case, an attempt to shift by a negative number of bits or by more bits than exist in the operand indicates a bug (logic error). These issues are covered by INT34-C. Do not shift a negative number of bits or more bits than exist in the operand.
Noncompliant Code Example
This noncompliant code example can result in an unrepresentable value.
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Compliant Solution
This compliant solution eliminates the possibility of overflow resulting from a left-shift operation:
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This section includes an example for the addition of atomic integer types only. For other operations, tests similar to the precondition tests for two’s complement integers used for nonatomic non-atomic integer types can be used.
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