SHSetUnreadMailCountW

// SHELL32.dll  (Unicode / -W)
#include <windows.h>

HRESULT SHSetUnreadMailCountW(
    LPCWSTR pszMailAddress,
    DWORD dwCount,
    LPCWSTR pszShellExecuteCommand
);

<DllImport("SHELL32.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function SHSetUnreadMailCountW(
    <MarshalAs(UnmanagedType.LPWStr)> pszMailAddress As String,   ' LPCWSTR
    dwCount As UInteger,   ' DWORD
    <MarshalAs(UnmanagedType.LPWStr)> pszShellExecuteCommand As String   ' LPCWSTR
) As Integer
End Function

' pszMailAddress : LPCWSTR
' dwCount : DWORD
' pszShellExecuteCommand : LPCWSTR
Declare PtrSafe Function SHSetUnreadMailCountW Lib "shell32" ( _
    ByVal pszMailAddress As LongPtr, _
    ByVal dwCount As Long, _
    ByVal pszShellExecuteCommand 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

SHSetUnreadMailCountW = ctypes.windll.shell32.SHSetUnreadMailCountW
SHSetUnreadMailCountW.restype = ctypes.c_int
SHSetUnreadMailCountW.argtypes = [
    wintypes.LPCWSTR,  # pszMailAddress : LPCWSTR
    wintypes.DWORD,  # dwCount : DWORD
    wintypes.LPCWSTR,  # pszShellExecuteCommand : LPCWSTR
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SHELL32.dll')
SHSetUnreadMailCountW = Fiddle::Function.new(
  lib['SHSetUnreadMailCountW'],
  [
    Fiddle::TYPE_VOIDP,  # pszMailAddress : LPCWSTR
    -Fiddle::TYPE_INT,  # dwCount : DWORD
    Fiddle::TYPE_VOIDP,  # pszShellExecuteCommand : LPCWSTR
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "shell32")]
extern "system" {
    fn SHSetUnreadMailCountW(
        pszMailAddress: *const u16,  // LPCWSTR
        dwCount: u32,  // DWORD
        pszShellExecuteCommand: *const u16  // LPCWSTR
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("SHELL32.dll", CharSet = CharSet.Unicode)]
public static extern int SHSetUnreadMailCountW([MarshalAs(UnmanagedType.LPWStr)] string pszMailAddress, uint dwCount, [MarshalAs(UnmanagedType.LPWStr)] string pszShellExecuteCommand);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SHELL32_SHSetUnreadMailCountW' -Namespace Win32 -PassThru
# $api::SHSetUnreadMailCountW(pszMailAddress, dwCount, pszShellExecuteCommand)

#uselib "SHELL32.dll"
#func global SHSetUnreadMailCountW "SHSetUnreadMailCountW" wptr, wptr, wptr
; SHSetUnreadMailCountW pszMailAddress, dwCount, pszShellExecuteCommand   ; 戻り値は stat
; pszMailAddress : LPCWSTR -> "wptr"
; dwCount : DWORD -> "wptr"
; pszShellExecuteCommand : 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 "SHELL32.dll"
#cfunc global SHSetUnreadMailCountW "SHSetUnreadMailCountW" wstr, int, wstr
; res = SHSetUnreadMailCountW(pszMailAddress, dwCount, pszShellExecuteCommand)
; pszMailAddress : LPCWSTR -> "wstr"
; dwCount : DWORD -> "int"
; pszShellExecuteCommand : LPCWSTR -> "wstr"

; HRESULT SHSetUnreadMailCountW(LPCWSTR pszMailAddress, DWORD dwCount, LPCWSTR pszShellExecuteCommand)
#uselib "SHELL32.dll"
#cfunc global SHSetUnreadMailCountW "SHSetUnreadMailCountW" wstr, int, wstr
; res = SHSetUnreadMailCountW(pszMailAddress, dwCount, pszShellExecuteCommand)
; pszMailAddress : LPCWSTR -> "wstr"
; dwCount : DWORD -> "int"
; pszShellExecuteCommand : LPCWSTR -> "wstr"

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

var (
	shell32 = windows.NewLazySystemDLL("SHELL32.dll")
	procSHSetUnreadMailCountW = shell32.NewProc("SHSetUnreadMailCountW")
)

// pszMailAddress (LPCWSTR), dwCount (DWORD), pszShellExecuteCommand (LPCWSTR)
r1, _, err := procSHSetUnreadMailCountW.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(pszMailAddress))),
	uintptr(dwCount),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(pszShellExecuteCommand))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function SHSetUnreadMailCountW(
  pszMailAddress: PWideChar;   // LPCWSTR
  dwCount: DWORD;   // DWORD
  pszShellExecuteCommand: PWideChar   // LPCWSTR
): Integer; stdcall;
  external 'SHELL32.dll' name 'SHSetUnreadMailCountW';

result := DllCall("SHELL32\SHSetUnreadMailCountW"
    , "WStr", pszMailAddress   ; LPCWSTR
    , "UInt", dwCount   ; DWORD
    , "WStr", pszShellExecuteCommand   ; LPCWSTR
    , "Int")   ; return: HRESULT

●SHSetUnreadMailCountW(pszMailAddress, dwCount, pszShellExecuteCommand) = DLL("SHELL32.dll", "int SHSetUnreadMailCountW(char*, dword, char*)")
# 呼び出し: SHSetUnreadMailCountW(pszMailAddress, dwCount, pszShellExecuteCommand)
# pszMailAddress : LPCWSTR -> "char*"
# dwCount : DWORD -> "dword"
# pszShellExecuteCommand : 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。