SetDllDirectoryW

// KERNEL32.dll  (Unicode / -W)
#include <windows.h>

BOOL SetDllDirectoryW(
    LPCWSTR lpPathName   // optional
);

<DllImport("KERNEL32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function SetDllDirectoryW(
    <MarshalAs(UnmanagedType.LPWStr)> lpPathName As String   ' LPCWSTR optional
) As Boolean
End Function

' lpPathName : LPCWSTR optional
Declare PtrSafe Function SetDllDirectoryW Lib "kernel32" ( _
    ByVal lpPathName As LongPtr) As Long
' 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

SetDllDirectoryW = ctypes.windll.kernel32.SetDllDirectoryW
SetDllDirectoryW.restype = wintypes.BOOL
SetDllDirectoryW.argtypes = [
    wintypes.LPCWSTR,  # lpPathName : LPCWSTR optional
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('KERNEL32.dll')
SetDllDirectoryW = Fiddle::Function.new(
  lib['SetDllDirectoryW'],
  [
    Fiddle::TYPE_VOIDP,  # lpPathName : LPCWSTR optional
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "kernel32")]
extern "system" {
    fn SetDllDirectoryW(
        lpPathName: *const u16  // LPCWSTR optional
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("KERNEL32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern bool SetDllDirectoryW([MarshalAs(UnmanagedType.LPWStr)] string lpPathName);
"@
$api = Add-Type -MemberDefinition $sig -Name 'KERNEL32_SetDllDirectoryW' -Namespace Win32 -PassThru
# $api::SetDllDirectoryW(lpPathName)

#uselib "KERNEL32.dll"
#func global SetDllDirectoryW "SetDllDirectoryW" wptr
; SetDllDirectoryW lpPathName   ; 戻り値は stat
; lpPathName : LPCWSTR optional -> "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 "KERNEL32.dll"
#cfunc global SetDllDirectoryW "SetDllDirectoryW" wstr
; res = SetDllDirectoryW(lpPathName)
; lpPathName : LPCWSTR optional -> "wstr"

; BOOL SetDllDirectoryW(LPCWSTR lpPathName)
#uselib "KERNEL32.dll"
#cfunc global SetDllDirectoryW "SetDllDirectoryW" wstr
; res = SetDllDirectoryW(lpPathName)
; lpPathName : LPCWSTR optional -> "wstr"

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

var (
	kernel32 = windows.NewLazySystemDLL("KERNEL32.dll")
	procSetDllDirectoryW = kernel32.NewProc("SetDllDirectoryW")
)

// lpPathName (LPCWSTR optional)
r1, _, err := procSetDllDirectoryW.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpPathName))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function SetDllDirectoryW(
  lpPathName: PWideChar   // LPCWSTR optional
): BOOL; stdcall;
  external 'KERNEL32.dll' name 'SetDllDirectoryW';

result := DllCall("KERNEL32\SetDllDirectoryW"
    , "WStr", lpPathName   ; LPCWSTR optional
    , "Int")   ; return: BOOL

●SetDllDirectoryW(lpPathName) = DLL("KERNEL32.dll", "bool SetDllDirectoryW(char*)")
# 呼び出し: SetDllDirectoryW(lpPathName)
# lpPathName : LPCWSTR optional -> "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。