Technical Perspective: STACKing Up Undefined Behaviors

Any computer system must make trade-offs between freedoms retained by the system and guarantees made to the system's users. Designers attempt to balance conflicting goals, such as throughput and ease of use. Programming languages must make these trade-offs too. For example, a language with built-in garbage collection often retains the freedom to move objects around in memory, making it difficult to share objects with other processes or with hardware devices. C and C are based on an extreme set of trade-offs: In these languages, a wide variety of hard-to-avoid program behaviors, such as signed integer overflow and out-of-bounds array references, are "undefined behaviors."