It probably is, unless you have done some extraordinary testing. In fact, the binary searches delivered with major products – Java, C – are broken, though the problem wasn’t found until recently.
This article discusses the origins of the binary search, the problems inherent with the standard search, how the problem was discovered, and what to do about it.
If you are a geek and nerd, a programmer, an IT specialist, or in any other way deal with search routines and code, you really need to read the article.
Here is the link to the article on broken binary search routines.