unumf_formatDouble

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

void unumf_formatDouble(
    const UNumberFormatter* uformatter,
    DOUBLE value,
    UFormattedNumber* uresult,
    UErrorCode* ec
);

<DllImport("icu.dll", ExactSpelling:=True, CallingConvention:=CallingConvention.Cdecl)>
Public Shared Sub unumf_formatDouble(
    ByRef uformatter As IntPtr,   ' UNumberFormatter*
    value As Double,   ' DOUBLE
    ByRef uresult As IntPtr,   ' UFormattedNumber* in/out
    ByRef ec As Integer   ' UErrorCode* in/out
)
End Sub

' uformatter : UNumberFormatter*
' value : DOUBLE
' uresult : UFormattedNumber* in/out
' ec : UErrorCode* in/out
Declare PtrSafe Sub unumf_formatDouble Lib "icu" ( _
    ByRef uformatter As LongPtr, _
    ByVal value As Double, _
    ByRef uresult As LongPtr, _
    ByRef ec As Long)
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

unumf_formatDouble = ctypes.cdll.icu.unumf_formatDouble
unumf_formatDouble.restype = None
unumf_formatDouble.argtypes = [
    ctypes.c_void_p,  # uformatter : UNumberFormatter*
    ctypes.c_double,  # value : DOUBLE
    ctypes.c_void_p,  # uresult : UFormattedNumber* in/out
    ctypes.c_void_p,  # ec : UErrorCode* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('icu.dll')
unumf_formatDouble = Fiddle::Function.new(
  lib['unumf_formatDouble'],
  [
    Fiddle::TYPE_VOIDP,  # uformatter : UNumberFormatter*
    Fiddle::TYPE_DOUBLE,  # value : DOUBLE
    Fiddle::TYPE_VOIDP,  # uresult : UFormattedNumber* in/out
    Fiddle::TYPE_VOIDP,  # ec : UErrorCode* in/out
  ],
  Fiddle::TYPE_VOID, Fiddle::Function::CDECL)

#[link(name = "icu")]
extern "C" {
    fn unumf_formatDouble(
        uformatter: *const isize,  // UNumberFormatter*
        value: f64,  // DOUBLE
        uresult: *mut isize,  // UFormattedNumber* in/out
        ec: *mut i32  // UErrorCode* in/out
    );
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("icu.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern void unumf_formatDouble(ref IntPtr uformatter, double value, ref IntPtr uresult, ref int ec);
"@
$api = Add-Type -MemberDefinition $sig -Name 'icu_unumf_formatDouble' -Namespace Win32 -PassThru
# $api::unumf_formatDouble(uformatter, value, uresult, ec)

#uselib "icu.dll"
#func global unumf_formatDouble "unumf_formatDouble" sptr, double, sptr, sptr
; unumf_formatDouble uformatter, value, uresult, ec
; uformatter : UNumberFormatter* -> "sptr"
; value : DOUBLE -> "double"
; uresult : UFormattedNumber* in/out -> "sptr"
; ec : UErrorCode* in/out -> "sptr"

#uselib "icu.dll"
#func global unumf_formatDouble "unumf_formatDouble" int, double, int, int
; unumf_formatDouble uformatter, value, uresult, ec
; uformatter : UNumberFormatter* -> "int"
; value : DOUBLE -> "double"
; uresult : UFormattedNumber* in/out -> "int"
; ec : UErrorCode* in/out -> "int"

; void unumf_formatDouble(UNumberFormatter* uformatter, DOUBLE value, UFormattedNumber* uresult, UErrorCode* ec)
#uselib "icu.dll"
#func global unumf_formatDouble "unumf_formatDouble" int, double, int, int
; unumf_formatDouble uformatter, value, uresult, ec
; uformatter : UNumberFormatter* -> "int"
; value : DOUBLE -> "double"
; uresult : UFormattedNumber* in/out -> "int"
; ec : UErrorCode* in/out -> "int"

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

var (
	icu = windows.NewLazySystemDLL("icu.dll")
	procunumf_formatDouble = icu.NewProc("unumf_formatDouble")
)

// uformatter (UNumberFormatter*), value (DOUBLE), uresult (UFormattedNumber* in/out), ec (UErrorCode* in/out)
r1, _, err := procunumf_formatDouble.Call(
	uintptr(uformatter),
	uintptr(math.Float64bits(value)),
	uintptr(uresult),
	uintptr(ec),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // void
// 注意: float/double 引数は proc.Call では XMM レジスタに渡せません。
// windows.SyscallN(proc.Addr(), math.Float64bits(x), ...) もしくは cgo を使用してください。

procedure unumf_formatDouble(
  uformatter: Pointer;   // UNumberFormatter*
  value: Double;   // DOUBLE
  uresult: Pointer;   // UFormattedNumber* in/out
  ec: Pointer   // UErrorCode* in/out
); cdecl;
  external 'icu.dll' name 'unumf_formatDouble';

result := DllCall("icu\unumf_formatDouble"
    , "Ptr", uformatter   ; UNumberFormatter*
    , "Double", value   ; DOUBLE
    , "Ptr", uresult   ; UFormattedNumber* in/out
    , "Ptr", ec   ; UErrorCode* in/out
    , "Cdecl Int")   ; return: void

●unumf_formatDouble(uformatter, value, uresult, ec) = DLL("icu.dll", "int unumf_formatDouble(void*, double, void*, void*)")
# 呼び出し: unumf_formatDouble(uformatter, value, uresult, ec)
# uformatter : UNumberFormatter* -> "void*"
# value : DOUBLE -> "double"
# uresult : UFormattedNumber* in/out -> "void*"
# ec : 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。