The general rule of unsafe api(usage) is "once you done it, nothing is expected to safe even if it was stated to be". Error can spread in your program in funny

The general rule of unsafe api(usage) is "once you done it, nothing is expected to safe even if it was stated to be". Error can spread in your program in funny way, which also break the program in funny way (think about stack overflow or double free). Unless the manual/document explicitly stated what error can it cause, there is no way to know without actually trigger it.