MsiQueryProductStateA

// msi.dll  (ANSI / -A)
#include <windows.h>

INSTALLSTATE MsiQueryProductStateA(
    LPCSTR szProduct
);

<DllImport("msi.dll", CharSet:=CharSet.Ansi, ExactSpelling:=True)>
Public Shared Function MsiQueryProductStateA(
    <MarshalAs(UnmanagedType.LPStr)> szProduct As String   ' LPCSTR
) As Integer
End Function

' szProduct : LPCSTR
Declare PtrSafe Function MsiQueryProductStateA Lib "msi" ( _
    ByVal szProduct As String) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

MsiQueryProductStateA = ctypes.windll.msi.MsiQueryProductStateA
MsiQueryProductStateA.restype = ctypes.c_int
MsiQueryProductStateA.argtypes = [
    wintypes.LPCSTR,  # szProduct : LPCSTR
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('msi.dll')
MsiQueryProductStateA = Fiddle::Function.new(
  lib['MsiQueryProductStateA'],
  [
    Fiddle::TYPE_VOIDP,  # szProduct : LPCSTR
  ],
  Fiddle::TYPE_INT)

#[link(name = "msi")]
extern "system" {
    fn MsiQueryProductStateA(
        szProduct: *const u8  // LPCSTR
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("msi.dll", CharSet = CharSet.Ansi)]
public static extern int MsiQueryProductStateA([MarshalAs(UnmanagedType.LPStr)] string szProduct);
"@
$api = Add-Type -MemberDefinition $sig -Name 'msi_MsiQueryProductStateA' -Namespace Win32 -PassThru
# $api::MsiQueryProductStateA(szProduct)

#uselib "msi.dll"
#func global MsiQueryProductStateA "MsiQueryProductStateA" sptr
; MsiQueryProductStateA szProduct   ; 戻り値は stat
; szProduct : LPCSTR -> "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 "msi.dll"
#cfunc global MsiQueryProductStateA "MsiQueryProductStateA" str
; res = MsiQueryProductStateA(szProduct)
; szProduct : LPCSTR -> "str"

; INSTALLSTATE MsiQueryProductStateA(LPCSTR szProduct)
#uselib "msi.dll"
#cfunc global MsiQueryProductStateA "MsiQueryProductStateA" str
; res = MsiQueryProductStateA(szProduct)
; szProduct : LPCSTR -> "str"

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

var (
	msi = windows.NewLazySystemDLL("msi.dll")
	procMsiQueryProductStateA = msi.NewProc("MsiQueryProductStateA")
)

// szProduct (LPCSTR)
r1, _, err := procMsiQueryProductStateA.Call(
	uintptr(unsafe.Pointer(windows.BytePtrFromString(szProduct))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INSTALLSTATE

function MsiQueryProductStateA(
  szProduct: PAnsiChar   // LPCSTR
): Integer; stdcall;
  external 'msi.dll' name 'MsiQueryProductStateA';

result := DllCall("msi\MsiQueryProductStateA"
    , "AStr", szProduct   ; LPCSTR
    , "Int")   ; return: INSTALLSTATE

●MsiQueryProductStateA(szProduct) = DLL("msi.dll", "int MsiQueryProductStateA(char*)")
# 呼び出し: MsiQueryProductStateA(szProduct)
# szProduct : LPCSTR -> "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)。