if tid == 0 {
		return nil, plainError("missing tid")
	}

	f := efaceOf(&fn)
	if f._type == nil || f._type.Kind_&abi.KindMask != abi.Func {
		return nil, plainError("fn must be a function")
	}
	fv := (*funcval)(f.data)

	a := efaceOf(&stackArgs)
	if a._type != nil && a._type.Kind_&abi.KindMask != abi.Pointer {
		return nil, plainError("args must be a pointer or nil")
	}
	argp := a.data

	parent_tid *int32
	flags      int32
	rtp        *rtprio
	spare      [3]uintptr
}

type thread int32 // long

type sigset struct {
	__bits [4]uint32
}

type stackt struct {
	ss_sp    uintptr
	ss_size  uintptr
	ss_flags int32
}

type siginfo struct {
	si_signo  int32
	si_errno  int32
	si_code   int32
	si_pid    int32
	si_uid    uint32
	si_status int32

	flags      int32
	pad_cgo_0  [4]byte
	rtp        *rtprio
	spare      [3]uintptr
}

type thread int64 // long

type sigset struct {
	__bits [4]uint32
}

type stackt struct {
	ss_sp     uintptr
	ss_size   uintptr
	ss_flags  int32
	pad_cgo_0 [4]byte
}

type siginfo struct {
	si_signo  int32
	si_errno  int32
	si_code   int32
	si_pid    int32
	si_uid    uint32

	_NOTE_TRIGGER = 0x1000000
)

type rtprio struct {
	_type uint16
	prio  uint16
}

type lwpparams struct {
	start_func uintptr
	arg        unsafe.Pointer
	stack      uintptr
	tid1       unsafe.Pointer // *int32
	tid2       unsafe.Pointer // *int32
}

type sigset struct {
	__bits [4]uint32
}

type stackt struct {
	ss_sp     uintptr
	ss_size   uintptr

	flags      int32
	pad_cgo_0  [4]byte
	rtp        *rtprio
	spare      [3]uintptr
}

type thread int64 // long

type sigset struct {
	__bits [4]uint32
}

type stackt struct {
	ss_sp     uintptr
	ss_size   uintptr
	ss_flags  int32
	pad_cgo_0 [4]byte
}

type siginfo struct {
	si_signo  int32
	si_errno  int32
	si_code   int32
	si_pid    int32
	si_uid    uint32

	// a dependency on the reflect package.
	syms = make(map[string]any, len(md.ptab))
	for _, ptab := range md.ptab {
		symName := resolveNameOff(unsafe.Pointer(md.types), ptab.name)
		t := toRType((*_type)(unsafe.Pointer(md.types))).typeOff(ptab.typ) // TODO can this stack of conversions be simpler?
		var val any
		valp := (*[2]unsafe.Pointer)(unsafe.Pointer(&val))
		(*valp)[0] = unsafe.Pointer(t)

		name := symName.Name()

	}
}

// cgoCheckTypedBlock checks the block of memory at src, for up to size bytes,
// and throws if it finds an unpinned Go pointer. The type of the memory is typ,
// and src is off bytes into that type.
//
//go:nosplit
//go:nowritebarrier
func cgoCheckTypedBlock(typ *_type, src unsafe.Pointer, off, size uintptr) {
	// Anything past typ.PtrBytes is not a pointer.
	if typ.PtrBytes <= off {
		return
	}