udatpg_getFieldDisplayName

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

INT udatpg_getFieldDisplayName(
    const void** dtpg,
    UDateTimePatternField field,
    UDateTimePGDisplayWidth width,
    WORD* fieldName,
    INT capacity,
    UErrorCode* pErrorCode
);

<DllImport("icu.dll", ExactSpelling:=True, CallingConvention:=CallingConvention.Cdecl)>
Public Shared Function udatpg_getFieldDisplayName(
    dtpg As IntPtr,   ' void**
    field As Integer,   ' UDateTimePatternField
    width As Integer,   ' UDateTimePGDisplayWidth
    ByRef fieldName As UShort,   ' WORD* in/out
    capacity As Integer,   ' INT
    ByRef pErrorCode As Integer   ' UErrorCode* in/out
) As Integer
End Function

' dtpg : void**
' field : UDateTimePatternField
' width : UDateTimePGDisplayWidth
' fieldName : WORD* in/out
' capacity : INT
' pErrorCode : UErrorCode* in/out
Declare PtrSafe Function udatpg_getFieldDisplayName Lib "icu" ( _
    ByVal dtpg As LongPtr, _
    ByVal field As Long, _
    ByVal width As Long, _
    ByRef fieldName As Integer, _
    ByVal capacity As Long, _
    ByRef pErrorCode As Long) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

udatpg_getFieldDisplayName = ctypes.cdll.icu.udatpg_getFieldDisplayName
udatpg_getFieldDisplayName.restype = ctypes.c_int
udatpg_getFieldDisplayName.argtypes = [
    ctypes.c_void_p,  # dtpg : void**
    ctypes.c_int,  # field : UDateTimePatternField
    ctypes.c_int,  # width : UDateTimePGDisplayWidth
    ctypes.POINTER(ctypes.c_ushort),  # fieldName : WORD* in/out
    ctypes.c_int,  # capacity : INT
    ctypes.c_void_p,  # pErrorCode : UErrorCode* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('icu.dll')
udatpg_getFieldDisplayName = Fiddle::Function.new(
  lib['udatpg_getFieldDisplayName'],
  [
    Fiddle::TYPE_VOIDP,  # dtpg : void**
    Fiddle::TYPE_INT,  # field : UDateTimePatternField
    Fiddle::TYPE_INT,  # width : UDateTimePGDisplayWidth
    Fiddle::TYPE_VOIDP,  # fieldName : WORD* in/out
    Fiddle::TYPE_INT,  # capacity : INT
    Fiddle::TYPE_VOIDP,  # pErrorCode : UErrorCode* in/out
  ],
  Fiddle::TYPE_INT, Fiddle::Function::CDECL)

#[link(name = "icu")]
extern "C" {
    fn udatpg_getFieldDisplayName(
        dtpg: *const *const (),  // void**
        field: i32,  // UDateTimePatternField
        width: i32,  // UDateTimePGDisplayWidth
        fieldName: *mut u16,  // WORD* in/out
        capacity: i32,  // INT
        pErrorCode: *mut i32  // UErrorCode* in/out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("icu.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern int udatpg_getFieldDisplayName(IntPtr dtpg, int field, int width, ref ushort fieldName, int capacity, ref int pErrorCode);
"@
$api = Add-Type -MemberDefinition $sig -Name 'icu_udatpg_getFieldDisplayName' -Namespace Win32 -PassThru
# $api::udatpg_getFieldDisplayName(dtpg, field, width, fieldName, capacity, pErrorCode)

#uselib "icu.dll"
#func global udatpg_getFieldDisplayName "udatpg_getFieldDisplayName" sptr, sptr, sptr, sptr, sptr, sptr
; udatpg_getFieldDisplayName dtpg, field, width, varptr(fieldName), capacity, pErrorCode   ; 戻り値は stat
; dtpg : void** -> "sptr"
; field : UDateTimePatternField -> "sptr"
; width : UDateTimePGDisplayWidth -> "sptr"
; fieldName : WORD* in/out -> "sptr"
; capacity : INT -> "sptr"
; pErrorCode : UErrorCode* in/out -> "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 "icu.dll"
#cfunc global udatpg_getFieldDisplayName "udatpg_getFieldDisplayName" sptr, int, int, var, int, int
; res = udatpg_getFieldDisplayName(dtpg, field, width, fieldName, capacity, pErrorCode)
; dtpg : void** -> "sptr"
; field : UDateTimePatternField -> "int"
; width : UDateTimePGDisplayWidth -> "int"
; fieldName : WORD* in/out -> "var"
; capacity : INT -> "int"
; pErrorCode : 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。

; INT udatpg_getFieldDisplayName(void** dtpg, UDateTimePatternField field, UDateTimePGDisplayWidth width, WORD* fieldName, INT capacity, UErrorCode* pErrorCode)
#uselib "icu.dll"
#cfunc global udatpg_getFieldDisplayName "udatpg_getFieldDisplayName" intptr, int, int, var, int, int
; res = udatpg_getFieldDisplayName(dtpg, field, width, fieldName, capacity, pErrorCode)
; dtpg : void** -> "intptr"
; field : UDateTimePatternField -> "int"
; width : UDateTimePGDisplayWidth -> "int"
; fieldName : WORD* in/out -> "var"
; capacity : INT -> "int"
; pErrorCode : 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 (
	icu = windows.NewLazySystemDLL("icu.dll")
	procudatpg_getFieldDisplayName = icu.NewProc("udatpg_getFieldDisplayName")
)

// dtpg (void**), field (UDateTimePatternField), width (UDateTimePGDisplayWidth), fieldName (WORD* in/out), capacity (INT), pErrorCode (UErrorCode* in/out)
r1, _, err := procudatpg_getFieldDisplayName.Call(
	uintptr(dtpg),
	uintptr(field),
	uintptr(width),
	uintptr(fieldName),
	uintptr(capacity),
	uintptr(pErrorCode),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function udatpg_getFieldDisplayName(
  dtpg: Pointer;   // void**
  field: Integer;   // UDateTimePatternField
  width: Integer;   // UDateTimePGDisplayWidth
  fieldName: Pointer;   // WORD* in/out
  capacity: Integer;   // INT
  pErrorCode: Pointer   // UErrorCode* in/out
): Integer; cdecl;
  external 'icu.dll' name 'udatpg_getFieldDisplayName';

result := DllCall("icu\udatpg_getFieldDisplayName"
    , "Ptr", dtpg   ; void**
    , "Int", field   ; UDateTimePatternField
    , "Int", width   ; UDateTimePGDisplayWidth
    , "Ptr", fieldName   ; WORD* in/out
    , "Int", capacity   ; INT
    , "Ptr", pErrorCode   ; UErrorCode* in/out
    , "Cdecl Int")   ; return: INT

●udatpg_getFieldDisplayName(dtpg, field, width, fieldName, capacity, pErrorCode) = DLL("icu.dll", "int udatpg_getFieldDisplayName(void*, int, int, void*, int, void*)")
# 呼び出し: udatpg_getFieldDisplayName(dtpg, field, width, fieldName, capacity, pErrorCode)
# dtpg : void** -> "void*"
# field : UDateTimePatternField -> "int"
# width : UDateTimePGDisplayWidth -> "int"
# fieldName : WORD* in/out -> "void*"
# capacity : INT -> "int"
# pErrorCode : 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。