Symbol: SYS___tfork
sys/kern/kern_pledge.c
258
[SYS___tfork] = PLEDGE_STDIO,
sys/sys/syscall_mi.h
215
int code = (p->p_flag & P_THREAD) ? SYS___tfork :
usr.bin/kdump/kdump.c
733
[SYS___tfork] = { Pptr, Psize },