u_strncpy

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

WORD* u_strncpy(
    WORD* dst,
    const WORD* src,
    INT n
);

<DllImport("icuuc.dll", ExactSpelling:=True, CallingConvention:=CallingConvention.Cdecl)>
Public Shared Function u_strncpy(
    ByRef dst As UShort,   ' WORD* in/out
    ByRef src As UShort,   ' WORD*
    n As Integer   ' INT
) As IntPtr
End Function

' dst : WORD* in/out
' src : WORD*
' n : INT
Declare PtrSafe Function u_strncpy Lib "icuuc" ( _
    ByRef dst As Integer, _
    ByRef src As Integer, _
    ByVal n As Long) As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

u_strncpy = ctypes.cdll.icuuc.u_strncpy
u_strncpy.restype = ctypes.c_void_p
u_strncpy.argtypes = [
    ctypes.POINTER(ctypes.c_ushort),  # dst : WORD* in/out
    ctypes.POINTER(ctypes.c_ushort),  # src : WORD*
    ctypes.c_int,  # n : INT
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('icuuc.dll')
u_strncpy = Fiddle::Function.new(
  lib['u_strncpy'],
  [
    Fiddle::TYPE_VOIDP,  # dst : WORD* in/out
    Fiddle::TYPE_VOIDP,  # src : WORD*
    Fiddle::TYPE_INT,  # n : INT
  ],
  Fiddle::TYPE_VOIDP, Fiddle::Function::CDECL)

#[link(name = "icuuc")]
extern "C" {
    fn u_strncpy(
        dst: *mut u16,  // WORD* in/out
        src: *const u16,  // WORD*
        n: i32  // INT
    ) -> *mut u16;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("icuuc.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern IntPtr u_strncpy(ref ushort dst, ref ushort src, int n);
"@
$api = Add-Type -MemberDefinition $sig -Name 'icuuc_u_strncpy' -Namespace Win32 -PassThru
# $api::u_strncpy(dst, src, n)

#uselib "icuuc.dll"
#func global u_strncpy "u_strncpy" sptr, sptr, sptr
; u_strncpy varptr(dst), varptr(src), n   ; 戻り値は stat
; dst : WORD* in/out -> "sptr"
; src : WORD* -> "sptr"
; n : INT -> "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 "icuuc.dll"
#cfunc global u_strncpy "u_strncpy" var, var, int
; res = u_strncpy(dst, src, n)
; dst : WORD* in/out -> "var"
; src : WORD* -> "var"
; n : INT -> "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。

; WORD* u_strncpy(WORD* dst, WORD* src, INT n)
#uselib "icuuc.dll"
#cfunc global u_strncpy "u_strncpy" var, var, int
; res = u_strncpy(dst, src, n)
; dst : WORD* in/out -> "var"
; src : WORD* -> "var"
; n : INT -> "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")
	procu_strncpy = icuuc.NewProc("u_strncpy")
)

// dst (WORD* in/out), src (WORD*), n (INT)
r1, _, err := procu_strncpy.Call(
	uintptr(dst),
	uintptr(src),
	uintptr(n),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // WORD*

function u_strncpy(
  dst: Pointer;   // WORD* in/out
  src: Pointer;   // WORD*
  n: Integer   // INT
): Pointer; cdecl;
  external 'icuuc.dll' name 'u_strncpy';

result := DllCall("icuuc\u_strncpy"
    , "Ptr", dst   ; WORD* in/out
    , "Ptr", src   ; WORD*
    , "Int", n   ; INT
    , "Cdecl Ptr")   ; return: WORD*

●u_strncpy(dst, src, n) = DLL("icuuc.dll", "void* u_strncpy(void*, void*, int)")
# 呼び出し: u_strncpy(dst, src, n)
# dst : WORD* in/out -> "void*"
# src : WORD* -> "void*"
# n : INT -> "int"
# 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。