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WinHttpQueryDataAvailable

関数

読み取り可能なデータのバイト数を問い合わせる。

DLLWINHTTP.dll呼出規約winapiSetLastErrorあり対応OSWindows XP 以降

シグネチャ

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

BOOL WinHttpQueryDataAvailable(
    void* hRequest,
    DWORD* lpdwNumberOfBytesAvailable
);

パラメーター

名前	型	方向
hRequest	void*	inout
lpdwNumberOfBytesAvailable	DWORD*	inout

戻り値の型: BOOL

各言語での呼び出し定義

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

BOOL WinHttpQueryDataAvailable(
    void* hRequest,
    DWORD* lpdwNumberOfBytesAvailable
);

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("WINHTTP.dll", SetLastError = true, ExactSpelling = true)]
static extern bool WinHttpQueryDataAvailable(
    IntPtr hRequest,   // void* in/out
    ref uint lpdwNumberOfBytesAvailable   // DWORD* in/out
);

<DllImport("WINHTTP.dll", SetLastError:=True, ExactSpelling:=True)>
Public Shared Function WinHttpQueryDataAvailable(
    hRequest As IntPtr,   ' void* in/out
    ByRef lpdwNumberOfBytesAvailable As UInteger   ' DWORD* in/out
) As Boolean
End Function

' hRequest : void* in/out
' lpdwNumberOfBytesAvailable : DWORD* in/out
Declare PtrSafe Function WinHttpQueryDataAvailable Lib "winhttp" ( _
    ByVal hRequest As LongPtr, _
    ByRef lpdwNumberOfBytesAvailable 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

WinHttpQueryDataAvailable = ctypes.windll.winhttp.WinHttpQueryDataAvailable
WinHttpQueryDataAvailable.restype = wintypes.BOOL
WinHttpQueryDataAvailable.argtypes = [
    ctypes.POINTER(None),  # hRequest : void* in/out
    ctypes.POINTER(wintypes.DWORD),  # lpdwNumberOfBytesAvailable : DWORD* in/out
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('WINHTTP.dll')
WinHttpQueryDataAvailable = Fiddle::Function.new(
  lib['WinHttpQueryDataAvailable'],
  [
    Fiddle::TYPE_VOIDP,  # hRequest : void* in/out
    Fiddle::TYPE_VOIDP,  # lpdwNumberOfBytesAvailable : DWORD* in/out
  ],
  Fiddle::TYPE_INT)

#[link(name = "winhttp")]
extern "system" {
    fn WinHttpQueryDataAvailable(
        hRequest: *mut (),  // void* in/out
        lpdwNumberOfBytesAvailable: *mut u32  // DWORD* in/out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("WINHTTP.dll", SetLastError = true)]
public static extern bool WinHttpQueryDataAvailable(IntPtr hRequest, ref uint lpdwNumberOfBytesAvailable);
"@
$api = Add-Type -MemberDefinition $sig -Name 'WINHTTP_WinHttpQueryDataAvailable' -Namespace Win32 -PassThru
# $api::WinHttpQueryDataAvailable(hRequest, lpdwNumberOfBytesAvailable)

#uselib "WINHTTP.dll"
#func global WinHttpQueryDataAvailable "WinHttpQueryDataAvailable" sptr, sptr
; WinHttpQueryDataAvailable hRequest, varptr(lpdwNumberOfBytesAvailable)   ; 戻り値は stat
; hRequest : void* in/out -> "sptr"
; lpdwNumberOfBytesAvailable : DWORD* 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。

出力引数:

#uselib "WINHTTP.dll"
#cfunc global WinHttpQueryDataAvailable "WinHttpQueryDataAvailable" sptr, var
; res = WinHttpQueryDataAvailable(hRequest, lpdwNumberOfBytesAvailable)
; hRequest : void* in/out -> "sptr"
; lpdwNumberOfBytesAvailable : DWORD* in/out -> "var"
; ※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。#uselib "WINHTTP.dll"
#cfunc global WinHttpQueryDataAvailable "WinHttpQueryDataAvailable" sptr, sptr
; res = WinHttpQueryDataAvailable(hRequest, varptr(lpdwNumberOfBytesAvailable))
; hRequest : void* in/out -> "sptr"
; lpdwNumberOfBytesAvailable : DWORD* in/out -> "sptr"
; ※出力/バッファ引数はポインタ方式(token=sptr / 呼び出しは varptr(変数))。

出力引数:

; BOOL WinHttpQueryDataAvailable(void* hRequest, DWORD* lpdwNumberOfBytesAvailable)
#uselib "WINHTTP.dll"
#cfunc global WinHttpQueryDataAvailable "WinHttpQueryDataAvailable" intptr, var
; res = WinHttpQueryDataAvailable(hRequest, lpdwNumberOfBytesAvailable)
; hRequest : void* in/out -> "intptr"
; lpdwNumberOfBytesAvailable : DWORD* in/out -> "var"
; ※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。; BOOL WinHttpQueryDataAvailable(void* hRequest, DWORD* lpdwNumberOfBytesAvailable)
#uselib "WINHTTP.dll"
#cfunc global WinHttpQueryDataAvailable "WinHttpQueryDataAvailable" intptr, intptr
; res = WinHttpQueryDataAvailable(hRequest, varptr(lpdwNumberOfBytesAvailable))
; hRequest : void* in/out -> "intptr"
; lpdwNumberOfBytesAvailable : DWORD* in/out -> "intptr"
; ※出力/バッファ引数はポインタ方式(token=intptr / 呼び出しは varptr(変数))。

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

var (
	winhttp = windows.NewLazySystemDLL("WINHTTP.dll")
	procWinHttpQueryDataAvailable = winhttp.NewProc("WinHttpQueryDataAvailable")
)

// hRequest (void* in/out), lpdwNumberOfBytesAvailable (DWORD* in/out)
r1, _, err := procWinHttpQueryDataAvailable.Call(
	uintptr(hRequest),
	uintptr(lpdwNumberOfBytesAvailable),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function WinHttpQueryDataAvailable(
  hRequest: Pointer;   // void* in/out
  lpdwNumberOfBytesAvailable: Pointer   // DWORD* in/out
): BOOL; stdcall;
  external 'WINHTTP.dll' name 'WinHttpQueryDataAvailable';

result := DllCall("WINHTTP\WinHttpQueryDataAvailable"
    , "Ptr", hRequest   ; void* in/out
    , "Ptr", lpdwNumberOfBytesAvailable   ; DWORD* in/out
    , "Int")   ; return: BOOL

●WinHttpQueryDataAvailable(hRequest, lpdwNumberOfBytesAvailable) = DLL("WINHTTP.dll", "bool WinHttpQueryDataAvailable(void*, void*)")
# 呼び出し: WinHttpQueryDataAvailable(hRequest, lpdwNumberOfBytesAvailable)
# hRequest : void* in/out -> "void*"
# lpdwNumberOfBytesAvailable : DWORD* 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)。