Unverified50% confidenceFactExact time
Undefined behavior (UB) in the C standard allows an implementation to do anything when it encounters that behavior, including producing seemingly correct output, crashing, silently corrupting data, or deleting the relevant code entirely after optimization.
1
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50%
Confidence
Long-term
Relevance
10/15/2026
First Seen
Sources
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Related Claims
UnverifiedUndefined behavior (UB) refers to operations for which the language specification explicitly does not guarantee any behavior, such as dereferencing a dangling pointer, data races, out-of-bounds access, etc.72% similarUnverifiedC 和 C++ 标准将有符号整数溢出定义为未定义行为（Undefined Behavior）67% similarUnverifiedIOCCC的许多极端技巧依赖C语言标准中的未定义行为（UB），利用UB的代码在不同编译器或优化级别下可能产生截然不同的输出65% similarUnverifiedThe C standard defines signed integer overflow as undefined behavior, allowing compilers to assume that loop counters never overflow in order to achieve better vectorization optimizations.64% similarUnverifiedExplicitly informing the model of the runtime environment in the prompt (e.g., Windows environment uses UTF-8 without BOM encoding) can reduce encoding errors caused by the model guessing on its own.58% similar
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