GetProcAddress

// KERNEL32.dll
#include <windows.h>

FARPROC GetProcAddress(
    HMODULE hModule,
    LPCSTR lpProcName
);

<DllImport("KERNEL32.dll", SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetProcAddress(
    hModule As IntPtr,   ' HMODULE
    <MarshalAs(UnmanagedType.LPStr)> lpProcName As String   ' LPCSTR
) As IntPtr
End Function

' hModule : HMODULE
' lpProcName : LPCSTR
Declare PtrSafe Function GetProcAddress Lib "kernel32" ( _
    ByVal hModule As LongPtr, _
    ByVal lpProcName As String) As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

GetProcAddress = ctypes.windll.kernel32.GetProcAddress
GetProcAddress.restype = ctypes.c_void_p
GetProcAddress.argtypes = [
    wintypes.HANDLE,  # hModule : HMODULE
    wintypes.LPCSTR,  # lpProcName : LPCSTR
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('KERNEL32.dll')
GetProcAddress = Fiddle::Function.new(
  lib['GetProcAddress'],
  [
    Fiddle::TYPE_VOIDP,  # hModule : HMODULE
    Fiddle::TYPE_VOIDP,  # lpProcName : LPCSTR
  ],
  Fiddle::TYPE_VOIDP)

#[link(name = "kernel32")]
extern "system" {
    fn GetProcAddress(
        hModule: *mut core::ffi::c_void,  // HMODULE
        lpProcName: *const u8  // LPCSTR
    ) -> *const core::ffi::c_void;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("KERNEL32.dll", SetLastError = true)]
public static extern IntPtr GetProcAddress(IntPtr hModule, [MarshalAs(UnmanagedType.LPStr)] string lpProcName);
"@
$api = Add-Type -MemberDefinition $sig -Name 'KERNEL32_GetProcAddress' -Namespace Win32 -PassThru
# $api::GetProcAddress(hModule, lpProcName)

#uselib "KERNEL32.dll"
#func global GetProcAddress "GetProcAddress" sptr, sptr
; GetProcAddress hModule, lpProcName   ; 戻り値は stat
; hModule : HMODULE -> "sptr"
; lpProcName : 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 "KERNEL32.dll"
#cfunc global GetProcAddress "GetProcAddress" sptr, str
; res = GetProcAddress(hModule, lpProcName)
; hModule : HMODULE -> "sptr"
; lpProcName : LPCSTR -> "str"

; FARPROC GetProcAddress(HMODULE hModule, LPCSTR lpProcName)
#uselib "KERNEL32.dll"
#cfunc global GetProcAddress "GetProcAddress" intptr, str
; res = GetProcAddress(hModule, lpProcName)
; hModule : HMODULE -> "intptr"
; lpProcName : LPCSTR -> "str"

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

var (
	kernel32 = windows.NewLazySystemDLL("KERNEL32.dll")
	procGetProcAddress = kernel32.NewProc("GetProcAddress")
)

// hModule (HMODULE), lpProcName (LPCSTR)
r1, _, err := procGetProcAddress.Call(
	uintptr(hModule),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(lpProcName))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // FARPROC

function GetProcAddress(
  hModule: THandle;   // HMODULE
  lpProcName: PAnsiChar   // LPCSTR
): Pointer; stdcall;
  external 'KERNEL32.dll' name 'GetProcAddress';

result := DllCall("KERNEL32\GetProcAddress"
    , "Ptr", hModule   ; HMODULE
    , "AStr", lpProcName   ; LPCSTR
    , "Ptr")   ; return: FARPROC

●GetProcAddress(hModule, lpProcName) = DLL("KERNEL32.dll", "void* GetProcAddress(void*, char*)")
# 呼び出し: GetProcAddress(hModule, lpProcName)
# hModule : HMODULE -> "void*"
# lpProcName : 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)。

const std = @import("std");

extern "kernel32" fn GetProcAddress(
    hModule: ?*anyopaque, // HMODULE
    lpProcName: [*c]const u8 // LPCSTR
) callconv(std.os.windows.WINAPI) ?*anyopaque;

proc GetProcAddress(
    hModule: pointer,  # HMODULE
    lpProcName: cstring  # LPCSTR
): pointer {.importc: "GetProcAddress", stdcall, dynlib: "KERNEL32.dll".}

pragma(lib, "kernel32");
extern(Windows)
void* GetProcAddress(
    void* hModule,   // HMODULE
    const(char)* lpProcName   // LPCSTR
);

ccall((:GetProcAddress, "KERNEL32.dll"), stdcall, Ptr{Cvoid},
      (Ptr{Cvoid}, Cstring),
      hModule, lpProcName)
# hModule : HMODULE -> Ptr{Cvoid}
# lpProcName : LPCSTR -> Cstring
# stdcall は 32bit のみ意味を持つ(x64 では無視)。

local ffi = require("ffi")
ffi.cdef[[
void* GetProcAddress(
    void* hModule,
    const char* lpProcName);
]]
local kernel32 = ffi.load("kernel32")
-- kernel32.GetProcAddress(hModule, lpProcName)
-- hModule : HMODULE
-- lpProcName : LPCSTR
-- 構造体/GUIDへのポインタは cdef が通るよう void* で表記(実型は各引数コメント参照)。値渡し構造体・enum は対応する typedef を cdef に追加すること。

const koffi = require('koffi');
const lib = koffi.load('KERNEL32.dll');
const GetProcAddress = lib.func('__stdcall', 'GetProcAddress', 'void *', ['void *', 'str']);
// GetProcAddress(hModule, lpProcName)
// hModule : HMODULE -> 'void *'
// lpProcName : LPCSTR -> 'str'
// 出力ポインタは koffi.out(...) で包む。構造体は koffi.struct で定義。

const lib = Deno.dlopen("KERNEL32.dll", {
  GetProcAddress: { parameters: ["pointer", "buffer"], result: "pointer" },
});
// lib.symbols.GetProcAddress(hModule, lpProcName)
// hModule : HMODULE -> "pointer"
// lpProcName : LPCSTR -> "buffer"
// 文字列引数は "buffer"(NUL 終端のバイト列を Uint8Array で渡す)。
// 値渡し構造体は { struct: [ ...field types... ] } を使用。

<?php
$ffi = FFI::cdef(<<<C
void* GetProcAddress(
    void* hModule,
    const char* lpProcName);
C, "KERNEL32.dll");
// $ffi->GetProcAddress(hModule, lpProcName);
// hModule : HMODULE
// lpProcName : LPCSTR
// 構造体/GUIDへのポインタは cdef が通るよう void* で表記(実型は各引数コメント参照)。値渡し構造体・enum は対応する typedef を cdef に追加すること。
// WINAPI(stdcall): x64 では呼出規約が統一されるため問題なし。x86 では __stdcall 対応のラッパが必要な場合あり。

import com.sun.jna.*;
import com.sun.jna.ptr.*;
import com.sun.jna.win32.StdCallLibrary;
import com.sun.jna.win32.W32APIOptions;

public interface Kernel32 extends StdCallLibrary {
    Kernel32 INSTANCE = Native.load("kernel32", Kernel32.class);
    Pointer GetProcAddress(
        Pointer hModule,   // HMODULE
        String lpProcName   // LPCSTR
    );
}

@[Link("kernel32")]
lib LibKERNEL32
  fun GetProcAddress = GetProcAddress(
    hModule : Void*,   # HMODULE
    lpProcName : UInt8*   # LPCSTR
  ) : Void*
end
# 構造体/GUID/enum は lib 内に対応する型定義が必要。
# 呼出規約: x64 は規約統一のため OK。x86(32bit)は WINAPI=stdcall だが Crystal の fun に stdcall 付与構文がなく非対応。

import 'dart:ffi';
import 'package:ffi/ffi.dart';

typedef GetProcAddressNative = Pointer<Void> Function(Pointer<Void>, Pointer<Utf8>);
typedef GetProcAddressDart = Pointer<Void> Function(Pointer<Void>, Pointer<Utf8>);
final GetProcAddress = DynamicLibrary.open('KERNEL32.dll')
    .lookupFunction<GetProcAddressNative, GetProcAddressDart>('GetProcAddress');
// hModule : HMODULE -> Pointer<Void>
// lpProcName : LPCSTR -> Pointer<Utf8>
// 文字列は package:ffi の "...".toNativeUtf16()/toNativeUtf8() で変換。

{$mode objfpc}{$H+}
function GetProcAddress(
  hModule: THandle;   // HMODULE
  lpProcName: PAnsiChar   // LPCSTR
): Pointer; stdcall;
  external 'KERNEL32.dll' name 'GetProcAddress';

import Foreign
import Foreign.C.Types
import Foreign.C.String

foreign import stdcall safe "GetProcAddress"
  c_GetProcAddress :: Ptr () -> CString -> IO (Ptr ())
-- hModule : HMODULE -> Ptr ()
-- lpProcName : LPCSTR -> CString
-- 要 GHC(Windows)。stdcall は x64 では ccall として扱われる。ブロックする API は safe 呼び出し推奨。

open Ctypes
open Foreign

let getprocaddress =
  foreign "GetProcAddress"
    ((ptr void) @-> string @-> returning (ptr void))
(* hModule : HMODULE -> (ptr void) *)
(* lpProcName : LPCSTR -> string *)
(* foreign は cdecl 前提。x64 Windows では WINAPI と一致。構造体は ctypes structure を定義のこと。 *)

(cffi:define-foreign-library kernel32 (t "KERNEL32.dll"))
(cffi:use-foreign-library kernel32)

(cffi:defcfun ("GetProcAddress" get-proc-address :convention :stdcall) :pointer
  (h-module :pointer)   ; HMODULE
  (lp-proc-name :string))   ; LPCSTR
; isize/usize(INT_PTR/SIZE_T)は x64 前提で :int64/:uint64。x86 では :int32/:uint32。

use Win32::API;
my $GetProcAddress = Win32::API::More->new('KERNEL32',
    'LPVOID GetProcAddress(HANDLE hModule, LPCSTR lpProcName)');
# my $ret = $GetProcAddress->Call($hModule, $lpProcName);
# hModule : HMODULE -> HANDLE
# lpProcName : LPCSTR -> LPCSTR
# 値渡し構造体は pack() した文字列、または Win32::API::Struct を使用。