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)。