c - WinHttpSendRequest 和 ERROR_WINHTTP_RESEND_REQUEST

Question

调用 WinHttpSendRequest 后 GetLastError() 是否可能返回 ERROR_WINHTTP_RESEND_REQUEST？

WinHttpSendRequest 的文档:

ERROR_WINHTTP_RESEND_REQUEST
The application must call WinHttpSendRequest again due to a redirect or authentication challenge. Windows Server 2003 with SP1, Windows XP with SP2 and Windows 2000:  This error is not supported.

但是来自 MSDN 的示例(WinHTTP 中的身份验证)会在 WinHttpReceiveResponse 之后检查此值。

Answer 1

But samples from MSDN (Authentication in WinHTTP) checks for this value after WinHttpReceiveResponse.

乍一看the sample可能看起来像那样。但是，如果您仔细观察，该示例实际上会检查 ERROR_WINHTTP_RESEND_REQUEST if either WinHttpSendRequest() 或 WinHttpReceiveResponse () 失败:

// Send a request.
bResults = WinHttpSendRequest( hRequest,
                               WINHTTP_NO_ADDITIONAL_HEADERS,
                               0,
                               WINHTTP_NO_REQUEST_DATA,
                               0, 
                               0, 
                               0 );

// End the request.
if( bResults )
  bResults = WinHttpReceiveResponse( hRequest, NULL );

// Resend the request in case of 
// ERROR_WINHTTP_RESEND_REQUEST error.
if( !bResults && GetLastError( ) == ERROR_WINHTTP_RESEND_REQUEST)
    continue;

如果 WinHttpSendRequest() 返回 FALSE，将跳过对 WinHttpReceiveResponse() 的调用并调用 GetLastError() 将检查 ERROR_WINHTTP_RESEND_REQUEST。此代码位于 while 循环内，因此 continue 语句将导致循环的剩余部分被跳过，因此 WinHttpSendRequest() 将是再次调用。

结论:样本与引用文档一致。