PTRACE_SYSCALL
if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0)
if ((p->p_ptevents & PTRACE_SYSCALL) != 0)
p->p_ptevents |= PTRACE_SYSCALL;
events &= ~PTRACE_SYSCALL;
events &= ~PTRACE_SYSCALL;