CharPrevW

// USER32.dll  (Unicode / -W)
#include <windows.h>

LPWSTR CharPrevW(
    LPCWSTR lpszStart,
    LPCWSTR lpszCurrent
);

<DllImport("USER32.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function CharPrevW(
    <MarshalAs(UnmanagedType.LPWStr)> lpszStart As String,   ' LPCWSTR
    <MarshalAs(UnmanagedType.LPWStr)> lpszCurrent As String   ' LPCWSTR
) As IntPtr
End Function

' lpszStart : LPCWSTR
' lpszCurrent : LPCWSTR
Declare PtrSafe Function CharPrevW Lib "user32" ( _
    ByVal lpszStart As LongPtr, _
    ByVal lpszCurrent As LongPtr) As LongPtr
' Unicode(W): 文字列は ByVal As LongPtr とし StrPtr(unicodeStr) を渡す
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

CharPrevW = ctypes.windll.user32.CharPrevW
CharPrevW.restype = wintypes.LPWSTR
CharPrevW.argtypes = [
    wintypes.LPCWSTR,  # lpszStart : LPCWSTR
    wintypes.LPCWSTR,  # lpszCurrent : LPCWSTR
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
CharPrevW = Fiddle::Function.new(
  lib['CharPrevW'],
  [
    Fiddle::TYPE_VOIDP,  # lpszStart : LPCWSTR
    Fiddle::TYPE_VOIDP,  # lpszCurrent : LPCWSTR
  ],
  Fiddle::TYPE_VOIDP)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "user32")]
extern "system" {
    fn CharPrevW(
        lpszStart: *const u16,  // LPCWSTR
        lpszCurrent: *const u16  // LPCWSTR
    ) -> *mut u16;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Unicode)]
public static extern IntPtr CharPrevW([MarshalAs(UnmanagedType.LPWStr)] string lpszStart, [MarshalAs(UnmanagedType.LPWStr)] string lpszCurrent);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_CharPrevW' -Namespace Win32 -PassThru
# $api::CharPrevW(lpszStart, lpszCurrent)

#uselib "USER32.dll"
#func global CharPrevW "CharPrevW" wptr, wptr
; CharPrevW lpszStart, lpszCurrent   ; 戻り値は stat
; lpszStart : LPCWSTR -> "wptr"
; lpszCurrent : LPCWSTR -> "wptr"
; ※HSP3.7は #func のため戻り値はシステム変数 stat に格納されます。

#uselib "USER32.dll"
#cfunc global CharPrevW "CharPrevW" wstr, wstr
; res = CharPrevW(lpszStart, lpszCurrent)
; lpszStart : LPCWSTR -> "wstr"
; lpszCurrent : LPCWSTR -> "wstr"

; LPWSTR CharPrevW(LPCWSTR lpszStart, LPCWSTR lpszCurrent)
#uselib "USER32.dll"
#cfunc global CharPrevW "CharPrevW" wstr, wstr
; res = CharPrevW(lpszStart, lpszCurrent)
; lpszStart : LPCWSTR -> "wstr"
; lpszCurrent : LPCWSTR -> "wstr"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procCharPrevW = user32.NewProc("CharPrevW")
)

// lpszStart (LPCWSTR), lpszCurrent (LPCWSTR)
r1, _, err := procCharPrevW.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszStart))),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszCurrent))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // LPWSTR

function CharPrevW(
  lpszStart: PWideChar;   // LPCWSTR
  lpszCurrent: PWideChar   // LPCWSTR
): PWideChar; stdcall;
  external 'USER32.dll' name 'CharPrevW';

result := DllCall("USER32\CharPrevW"
    , "WStr", lpszStart   ; LPCWSTR
    , "WStr", lpszCurrent   ; LPCWSTR
    , "Ptr")   ; return: LPWSTR

●CharPrevW(lpszStart, lpszCurrent) = DLL("USER32.dll", "char* CharPrevW(char*, char*)")
# 呼び出し: CharPrevW(lpszStart, lpszCurrent)
# lpszStart : LPCWSTR -> "char*"
# lpszCurrent : LPCWSTR -> "char*"
# 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)。
# ※-W(Unicode)関数。なでしこ1はANSIのため -A 版の利用を推奨。