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13.2 Integer Overflow

In practice many portable C programs assume that signed integer overflow wraps around reliably using two’s complement arithmetic. Yet the C standard says that program behavior is undefined on overflow, and in a few cases C programs do not work on some modern implementations because their overflows do not wrap around as their authors expected. Conversely, in signed integer remainder, the C standard requires overflow behavior that is commonly not implemented.

• Basics of Integer Overflow
• Examples of Code Assuming Wraparound Overflow
• Optimizations That Break Wraparound Arithmetic
• Practical Advice for Signed Overflow Issues
• Signed Integer Division and Integer Overflow