It's a common idiom, specifically in modern C code. See "C Interfaces and Implementations", one of the best books on the subject of writing reusable C. The auth

It's a common idiom, specifically in modern C code. See "C Interfaces and Implementations", one of the best books on the subject of writing reusable C. The author dedicates an entire chapter to exception handling, with longjmp as the primarily facility for it.