> No; this is a common misconception I see from people who swallowed the "it's allowed to format your hard drive and blow up your monitor" dodge vs. the electri

> No; this is a common misconception I see from people who swallowed the "it's allowed to format your hard drive and blow up your monitor" dodge vs. the electrical engineers who know where terminology like 'undefined behavior' originated in engineering. In practice, it tends to do something subtle and usually right but probably wrong for the simple, practical reason that if it did anything as obviously wrong as "format your hard drive and blow up your monitor," someone would have tripped over it testing the compiler and changed the compiler. This is incorrect. In one very popular web server, some behavior depends on the values set for some response headers, and the value is checked in part by calling a function like strstr which takes two pointers and two lengths and searches one string for the other string. If you pass {null, 0} as the haystack and the implementation of the strstr-like function starts by computing the upper bound of the haystack (null + 0) then the compiler can legally produce *any value* for that expression. Then your program will quite predictably segfault. When it does your recourse is to fix your program, not to fix the compiler, because the compiler is working correctly.