ucnv_setSubstString

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

void ucnv_setSubstString(
    UConverter* cnv,
    const WORD* s,
    INT length,
    UErrorCode* err
);

<DllImport("icuuc.dll", ExactSpelling:=True, CallingConvention:=CallingConvention.Cdecl)>
Public Shared Sub ucnv_setSubstString(
    ByRef cnv As IntPtr,   ' UConverter* in/out
    ByRef s As UShort,   ' WORD*
    length As Integer,   ' INT
    ByRef err As Integer   ' UErrorCode* in/out
)
End Sub

' cnv : UConverter* in/out
' s : WORD*
' length : INT
' err : UErrorCode* in/out
Declare PtrSafe Sub ucnv_setSubstString Lib "icuuc" ( _
    ByRef cnv As LongPtr, _
    ByRef s As Integer, _
    ByVal length As Long, _
    ByRef err As Long)
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

ucnv_setSubstString = ctypes.cdll.icuuc.ucnv_setSubstString
ucnv_setSubstString.restype = None
ucnv_setSubstString.argtypes = [
    ctypes.c_void_p,  # cnv : UConverter* in/out
    ctypes.POINTER(ctypes.c_ushort),  # s : WORD*
    ctypes.c_int,  # length : INT
    ctypes.c_void_p,  # err : UErrorCode* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('icuuc.dll')
ucnv_setSubstString = Fiddle::Function.new(
  lib['ucnv_setSubstString'],
  [
    Fiddle::TYPE_VOIDP,  # cnv : UConverter* in/out
    Fiddle::TYPE_VOIDP,  # s : WORD*
    Fiddle::TYPE_INT,  # length : INT
    Fiddle::TYPE_VOIDP,  # err : UErrorCode* in/out
  ],
  Fiddle::TYPE_VOID, Fiddle::Function::CDECL)

#[link(name = "icuuc")]
extern "C" {
    fn ucnv_setSubstString(
        cnv: *mut isize,  // UConverter* in/out
        s: *const u16,  // WORD*
        length: i32,  // INT
        err: *mut i32  // UErrorCode* in/out
    );
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("icuuc.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern void ucnv_setSubstString(ref IntPtr cnv, ref ushort s, int length, ref int err);
"@
$api = Add-Type -MemberDefinition $sig -Name 'icuuc_ucnv_setSubstString' -Namespace Win32 -PassThru
# $api::ucnv_setSubstString(cnv, s, length, err)

#uselib "icuuc.dll"
#func global ucnv_setSubstString "ucnv_setSubstString" sptr, sptr, sptr, sptr
; ucnv_setSubstString cnv, varptr(s), length, err
; cnv : UConverter* in/out -> "sptr"
; s : WORD* -> "sptr"
; length : INT -> "sptr"
; err : UErrorCode* in/out -> "sptr"

#uselib "icuuc.dll"
#func global ucnv_setSubstString "ucnv_setSubstString" int, var, int, int
; ucnv_setSubstString cnv, s, length, err
; cnv : UConverter* in/out -> "int"
; s : WORD* -> "var"
; length : INT -> "int"
; err : UErrorCode* in/out -> "int"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

; void ucnv_setSubstString(UConverter* cnv, WORD* s, INT length, UErrorCode* err)
#uselib "icuuc.dll"
#func global ucnv_setSubstString "ucnv_setSubstString" int, var, int, int
; ucnv_setSubstString cnv, s, length, err
; cnv : UConverter* in/out -> "int"
; s : WORD* -> "var"
; length : INT -> "int"
; err : UErrorCode* in/out -> "int"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

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

var (
	icuuc = windows.NewLazySystemDLL("icuuc.dll")
	procucnv_setSubstString = icuuc.NewProc("ucnv_setSubstString")
)

// cnv (UConverter* in/out), s (WORD*), length (INT), err (UErrorCode* in/out)
r1, _, err := procucnv_setSubstString.Call(
	uintptr(cnv),
	uintptr(s),
	uintptr(length),
	uintptr(err),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // void

procedure ucnv_setSubstString(
  cnv: Pointer;   // UConverter* in/out
  s: Pointer;   // WORD*
  length: Integer;   // INT
  err: Pointer   // UErrorCode* in/out
); cdecl;
  external 'icuuc.dll' name 'ucnv_setSubstString';

result := DllCall("icuuc\ucnv_setSubstString"
    , "Ptr", cnv   ; UConverter* in/out
    , "Ptr", s   ; WORD*
    , "Int", length   ; INT
    , "Ptr", err   ; UErrorCode* in/out
    , "Cdecl Int")   ; return: void

●ucnv_setSubstString(cnv, s, length, err) = DLL("icuuc.dll", "int ucnv_setSubstString(void*, void*, int, void*)")
# 呼び出し: ucnv_setSubstString(cnv, s, length, err)
# cnv : UConverter* in/out -> "void*"
# s : WORD* -> "void*"
# length : INT -> "int"
# err : UErrorCode* in/out -> "void*"
# 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)。
# ※cdecl関数。DLL()宣言はstdcall前提。cdeclは EXEC_PTR(`cdecl`,…) を使用。