The C API for syscalls is mostly (almost entirely) just thin, 1:1 wrappers around the system calls themselves. In FreeBSD most of it is automatically generated

The C API for syscalls is mostly (almost entirely) just thin, 1:1 wrappers around the system calls themselves. In FreeBSD most of it is automatically generated from the same sys/kern/syscalls.master file that is used to generate the kernel syscall table.