SetEnvironmentVariableW

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

BOOL SetEnvironmentVariableW(
    LPCWSTR lpName,
    LPCWSTR lpValue   // optional
);

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

' lpName : LPCWSTR
' lpValue : LPCWSTR optional
Declare PtrSafe Function SetEnvironmentVariableW Lib "kernel32" ( _
    ByVal lpName As LongPtr, _
    ByVal lpValue 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

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

require 'fiddle'
require 'fiddle/import'

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

#[link(name = "kernel32")]
extern "system" {
    fn SetEnvironmentVariableW(
        lpName: *const u16,  // LPCWSTR
        lpValue: *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 SetEnvironmentVariableW([MarshalAs(UnmanagedType.LPWStr)] string lpName, [MarshalAs(UnmanagedType.LPWStr)] string lpValue);
"@
$api = Add-Type -MemberDefinition $sig -Name 'KERNEL32_SetEnvironmentVariableW' -Namespace Win32 -PassThru
# $api::SetEnvironmentVariableW(lpName, lpValue)

#uselib "KERNEL32.dll"
#func global SetEnvironmentVariableW "SetEnvironmentVariableW" wptr, wptr
; SetEnvironmentVariableW lpName, lpValue   ; 戻り値は stat
; lpName : LPCWSTR -> "wptr"
; lpValue : 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 SetEnvironmentVariableW "SetEnvironmentVariableW" wstr, wstr
; res = SetEnvironmentVariableW(lpName, lpValue)
; lpName : LPCWSTR -> "wstr"
; lpValue : LPCWSTR optional -> "wstr"

; BOOL SetEnvironmentVariableW(LPCWSTR lpName, LPCWSTR lpValue)
#uselib "KERNEL32.dll"
#cfunc global SetEnvironmentVariableW "SetEnvironmentVariableW" wstr, wstr
; res = SetEnvironmentVariableW(lpName, lpValue)
; lpName : LPCWSTR -> "wstr"
; lpValue : LPCWSTR optional -> "wstr"

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

var (
	kernel32 = windows.NewLazySystemDLL("KERNEL32.dll")
	procSetEnvironmentVariableW = kernel32.NewProc("SetEnvironmentVariableW")
)

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

function SetEnvironmentVariableW(
  lpName: PWideChar;   // LPCWSTR
  lpValue: PWideChar   // LPCWSTR optional
): BOOL; stdcall;
  external 'KERNEL32.dll' name 'SetEnvironmentVariableW';

result := DllCall("KERNEL32\SetEnvironmentVariableW"
    , "WStr", lpName   ; LPCWSTR
    , "WStr", lpValue   ; LPCWSTR optional
    , "Int")   ; return: BOOL

●SetEnvironmentVariableW(lpName, lpValue) = DLL("KERNEL32.dll", "bool SetEnvironmentVariableW(char*, char*)")
# 呼び出し: SetEnvironmentVariableW(lpName, lpValue)
# lpName : LPCWSTR -> "char*"
# lpValue : 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。