InternetCloseHandle function (wininet.h)

Article
10/13/2021

Closes a single Internet handle.

Syntax

BOOL InternetCloseHandle(
  [in] HINTERNET hInternet
);

Parameters

[in] hInternet

Handle to be closed.

Return value

Returns TRUE if the handle is successfully closed, or FALSE otherwise. To get extended error information, call GetLastError.

Remarks

The function terminates any pending operations on the handle and discards any outstanding data.

It is safe to call InternetCloseHandle as long as no API calls are being made or will be made using the handle. Once an API has returned ERROR_IO_PENDING, it is safe to call InternetCloseHandle to cancel that I/O, as long as no subsequent API calls will be issued with the handle.

It is safe to call InternetCloseHandle in a callback for the handle being closed. If there is a status callback registered for the handle being closed, and the handle was created with a non-NULL context value, an INTERNET_STATUS_HANDLE_CLOSING callback will be made. This indication will be the last callback made from a handle and indicates that the handle is being destroyed.

If asynchronous requests are pending for the handle or any of its child handles, the handle cannot be closed immediately, but it will be invalidated. Any new requests attempted using the handle will return with an ERROR_INVALID_HANDLE notification. The asynchronous requests will complete with INTERNET_STATUS_REQUEST_COMPLETE. Applications must be prepared to receive any INTERNET_STATUS_REQUEST_COMPLETE indications on the handle before the final INTERNET_STATUS_HANDLE_CLOSING indication is made, which indicates that the handle is completely closed.

An application can call GetLastError to determine if requests are pending. If GetLastError returns ERROR_IO_PENDING, there were outstanding requests when the handle was closed.

Like all other aspects of the WinINet API, this function cannot be safely called from within DllMain or the constructors and destructors of global objects.

Note WinINet does not support server implementations. In addition, it should not be used from a service. For server implementations or services use Microsoft Windows HTTP Services (WinHTTP).

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	wininet.h
Library	Wininet.lib
DLL	Wininet.dll