CharPrevExA

// USER32.dll
#include <windows.h>

LPSTR CharPrevExA(
    WORD CodePage,
    LPCSTR lpStart,
    LPCSTR lpCurrentChar,
    DWORD dwFlags
);

<DllImport("USER32.dll", ExactSpelling:=True)>
Public Shared Function CharPrevExA(
    CodePage As UShort,   ' WORD
    <MarshalAs(UnmanagedType.LPStr)> lpStart As String,   ' LPCSTR
    <MarshalAs(UnmanagedType.LPStr)> lpCurrentChar As String,   ' LPCSTR
    dwFlags As UInteger   ' DWORD
) As IntPtr
End Function

' CodePage : WORD
' lpStart : LPCSTR
' lpCurrentChar : LPCSTR
' dwFlags : DWORD
Declare PtrSafe Function CharPrevExA Lib "user32" ( _
    ByVal CodePage As Integer, _
    ByVal lpStart As String, _
    ByVal lpCurrentChar As String, _
    ByVal dwFlags As Long) As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

CharPrevExA = ctypes.windll.user32.CharPrevExA
CharPrevExA.restype = wintypes.LPSTR
CharPrevExA.argtypes = [
    ctypes.c_ushort,  # CodePage : WORD
    wintypes.LPCSTR,  # lpStart : LPCSTR
    wintypes.LPCSTR,  # lpCurrentChar : LPCSTR
    wintypes.DWORD,  # dwFlags : DWORD
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
CharPrevExA = Fiddle::Function.new(
  lib['CharPrevExA'],
  [
    -Fiddle::TYPE_SHORT,  # CodePage : WORD
    Fiddle::TYPE_VOIDP,  # lpStart : LPCSTR
    Fiddle::TYPE_VOIDP,  # lpCurrentChar : LPCSTR
    -Fiddle::TYPE_INT,  # dwFlags : DWORD
  ],
  Fiddle::TYPE_VOIDP)

#[link(name = "user32")]
extern "system" {
    fn CharPrevExA(
        CodePage: u16,  // WORD
        lpStart: *const u8,  // LPCSTR
        lpCurrentChar: *const u8,  // LPCSTR
        dwFlags: u32  // DWORD
    ) -> *mut u8;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll")]
public static extern IntPtr CharPrevExA(ushort CodePage, [MarshalAs(UnmanagedType.LPStr)] string lpStart, [MarshalAs(UnmanagedType.LPStr)] string lpCurrentChar, uint dwFlags);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_CharPrevExA' -Namespace Win32 -PassThru
# $api::CharPrevExA(CodePage, lpStart, lpCurrentChar, dwFlags)

#uselib "USER32.dll"
#func global CharPrevExA "CharPrevExA" sptr, sptr, sptr, sptr
; CharPrevExA CodePage, lpStart, lpCurrentChar, dwFlags   ; 戻り値は stat
; CodePage : WORD -> "sptr"
; lpStart : LPCSTR -> "sptr"
; lpCurrentChar : LPCSTR -> "sptr"
; dwFlags : DWORD -> "sptr"
; ※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 CharPrevExA "CharPrevExA" int, str, str, int
; res = CharPrevExA(CodePage, lpStart, lpCurrentChar, dwFlags)
; CodePage : WORD -> "int"
; lpStart : LPCSTR -> "str"
; lpCurrentChar : LPCSTR -> "str"
; dwFlags : DWORD -> "int"

; LPSTR CharPrevExA(WORD CodePage, LPCSTR lpStart, LPCSTR lpCurrentChar, DWORD dwFlags)
#uselib "USER32.dll"
#cfunc global CharPrevExA "CharPrevExA" int, str, str, int
; res = CharPrevExA(CodePage, lpStart, lpCurrentChar, dwFlags)
; CodePage : WORD -> "int"
; lpStart : LPCSTR -> "str"
; lpCurrentChar : LPCSTR -> "str"
; dwFlags : DWORD -> "int"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procCharPrevExA = user32.NewProc("CharPrevExA")
)

// CodePage (WORD), lpStart (LPCSTR), lpCurrentChar (LPCSTR), dwFlags (DWORD)
r1, _, err := procCharPrevExA.Call(
	uintptr(CodePage),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(lpStart))),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(lpCurrentChar))),
	uintptr(dwFlags),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // LPSTR

function CharPrevExA(
  CodePage: Word;   // WORD
  lpStart: PAnsiChar;   // LPCSTR
  lpCurrentChar: PAnsiChar;   // LPCSTR
  dwFlags: DWORD   // DWORD
): PAnsiChar; stdcall;
  external 'USER32.dll' name 'CharPrevExA';

result := DllCall("USER32\CharPrevExA"
    , "UShort", CodePage   ; WORD
    , "AStr", lpStart   ; LPCSTR
    , "AStr", lpCurrentChar   ; LPCSTR
    , "UInt", dwFlags   ; DWORD
    , "Ptr")   ; return: LPSTR

●CharPrevExA(CodePage, lpStart, lpCurrentChar, dwFlags) = DLL("USER32.dll", "char* CharPrevExA(int, char*, char*, dword)")
# 呼び出し: CharPrevExA(CodePage, lpStart, lpCurrentChar, dwFlags)
# CodePage : WORD -> "int"
# lpStart : LPCSTR -> "char*"
# lpCurrentChar : LPCSTR -> "char*"
# dwFlags : DWORD -> "dword"
# 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)。