The signal handling facilities allow the client OS to provide compatibility with POSIX style signal handling semantics. The support provided is extremely basic and is intended to be used in conjunction with the OSKit's FreeBSD C library (see Section 13) by arranging for unexpected hardware traps to be converted into an appropriate signal and delivered through the C library. By default, the FreeBSD C library will not arrange for signals to be delivered unless the oskit_init_libc initialization routine is called (see 9.9.1). The exception are kernels linked with the POSIX threads module, which will always call the initialization routine.