ColorRGBToHLS

// SHLWAPI.dll
#include <windows.h>

void ColorRGBToHLS(
    COLORREF clrRGB,
    WORD* pwHue,
    WORD* pwLuminance,
    WORD* pwSaturation
);

<DllImport("SHLWAPI.dll", ExactSpelling:=True)>
Public Shared Sub ColorRGBToHLS(
    clrRGB As UInteger,   ' COLORREF
    <Out> ByRef pwHue As UShort,   ' WORD* out
    <Out> ByRef pwLuminance As UShort,   ' WORD* out
    <Out> ByRef pwSaturation As UShort   ' WORD* out
)
End Sub

' clrRGB : COLORREF
' pwHue : WORD* out
' pwLuminance : WORD* out
' pwSaturation : WORD* out
Declare PtrSafe Sub ColorRGBToHLS Lib "shlwapi" ( _
    ByVal clrRGB As Long, _
    ByRef pwHue As Integer, _
    ByRef pwLuminance As Integer, _
    ByRef pwSaturation As Integer)
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

ColorRGBToHLS = ctypes.windll.shlwapi.ColorRGBToHLS
ColorRGBToHLS.restype = None
ColorRGBToHLS.argtypes = [
    wintypes.DWORD,  # clrRGB : COLORREF
    ctypes.POINTER(ctypes.c_ushort),  # pwHue : WORD* out
    ctypes.POINTER(ctypes.c_ushort),  # pwLuminance : WORD* out
    ctypes.POINTER(ctypes.c_ushort),  # pwSaturation : WORD* out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SHLWAPI.dll')
ColorRGBToHLS = Fiddle::Function.new(
  lib['ColorRGBToHLS'],
  [
    -Fiddle::TYPE_INT,  # clrRGB : COLORREF
    Fiddle::TYPE_VOIDP,  # pwHue : WORD* out
    Fiddle::TYPE_VOIDP,  # pwLuminance : WORD* out
    Fiddle::TYPE_VOIDP,  # pwSaturation : WORD* out
  ],
  Fiddle::TYPE_VOID)

#[link(name = "shlwapi")]
extern "system" {
    fn ColorRGBToHLS(
        clrRGB: u32,  // COLORREF
        pwHue: *mut u16,  // WORD* out
        pwLuminance: *mut u16,  // WORD* out
        pwSaturation: *mut u16  // WORD* out
    );
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("SHLWAPI.dll")]
public static extern void ColorRGBToHLS(uint clrRGB, out ushort pwHue, out ushort pwLuminance, out ushort pwSaturation);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SHLWAPI_ColorRGBToHLS' -Namespace Win32 -PassThru
# $api::ColorRGBToHLS(clrRGB, pwHue, pwLuminance, pwSaturation)

#uselib "SHLWAPI.dll"
#func global ColorRGBToHLS "ColorRGBToHLS" sptr, sptr, sptr, sptr
; ColorRGBToHLS clrRGB, varptr(pwHue), varptr(pwLuminance), varptr(pwSaturation)
; clrRGB : COLORREF -> "sptr"
; pwHue : WORD* out -> "sptr"
; pwLuminance : WORD* out -> "sptr"
; pwSaturation : WORD* out -> "sptr"

#uselib "SHLWAPI.dll"
#func global ColorRGBToHLS "ColorRGBToHLS" int, var, var, var
; ColorRGBToHLS clrRGB, pwHue, pwLuminance, pwSaturation
; clrRGB : COLORREF -> "int"
; pwHue : WORD* out -> "var"
; pwLuminance : WORD* out -> "var"
; pwSaturation : WORD* out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

; void ColorRGBToHLS(COLORREF clrRGB, WORD* pwHue, WORD* pwLuminance, WORD* pwSaturation)
#uselib "SHLWAPI.dll"
#func global ColorRGBToHLS "ColorRGBToHLS" int, var, var, var
; ColorRGBToHLS clrRGB, pwHue, pwLuminance, pwSaturation
; clrRGB : COLORREF -> "int"
; pwHue : WORD* out -> "var"
; pwLuminance : WORD* out -> "var"
; pwSaturation : WORD* out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	shlwapi = windows.NewLazySystemDLL("SHLWAPI.dll")
	procColorRGBToHLS = shlwapi.NewProc("ColorRGBToHLS")
)

// clrRGB (COLORREF), pwHue (WORD* out), pwLuminance (WORD* out), pwSaturation (WORD* out)
r1, _, err := procColorRGBToHLS.Call(
	uintptr(clrRGB),
	uintptr(pwHue),
	uintptr(pwLuminance),
	uintptr(pwSaturation),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // void

procedure ColorRGBToHLS(
  clrRGB: DWORD;   // COLORREF
  pwHue: Pointer;   // WORD* out
  pwLuminance: Pointer;   // WORD* out
  pwSaturation: Pointer   // WORD* out
); stdcall;
  external 'SHLWAPI.dll' name 'ColorRGBToHLS';

result := DllCall("SHLWAPI\ColorRGBToHLS"
    , "UInt", clrRGB   ; COLORREF
    , "Ptr", pwHue   ; WORD* out
    , "Ptr", pwLuminance   ; WORD* out
    , "Ptr", pwSaturation   ; WORD* out
    , "Int")   ; return: void

●ColorRGBToHLS(clrRGB, pwHue, pwLuminance, pwSaturation) = DLL("SHLWAPI.dll", "int ColorRGBToHLS(dword, void*, void*, void*)")
# 呼び出し: ColorRGBToHLS(clrRGB, pwHue, pwLuminance, pwSaturation)
# clrRGB : COLORREF -> "dword"
# pwHue : WORD* out -> "void*"
# pwLuminance : WORD* out -> "void*"
# pwSaturation : WORD* out -> "void*"
# なでしこ1は32bit・ANSI(Shift_JIS)。文字列=char*(ANSI)、ポインタ/ハンドル=void*(4byte)。