Function register_winapi_error_to_buffer

lib/hidapi/windows/hid.c:229–283

}

static void register_winapi_error_to_buffer(wchar_t **error_buffer, const WCHAR *op)
{
	free(*error_buffer);
	*error_buffer = NULL;

	/* Only clear out error messages if NULL is passed into op */
	if (!op) {
		return;
	}

	WCHAR system_err_buf[1024];
	DWORD error_code = GetLastError();

	DWORD system_err_len = FormatMessageW(
		FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
		NULL,
		error_code,
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
		system_err_buf, ARRAYSIZE(system_err_buf),
		NULL);

	DWORD op_len = (DWORD)wcslen(op);

	DWORD op_prefix_len =
		op_len
		+ 15 /*: (0x00000000) */
		;
	DWORD msg_len =
		+ op_prefix_len
		+ system_err_len
		;

	*error_buffer = (WCHAR *)calloc(msg_len + 1, sizeof (WCHAR));
	WCHAR *msg = *error_buffer;

	if (!msg)
		return;

	int printf_written = swprintf(msg, msg_len + 1, L"%.*ls: (0x%08X) %.*ls", (int)op_len, op, error_code, (int)system_err_len, system_err_buf);

	if (printf_written < 0)
	{
		/* Highly unlikely */
		msg[0] = L'\0';
		return;
	}

	/* Get rid of the CR and LF that FormatMessage() sticks at the
	   end of the message. Thanks Microsoft! */
	while(msg[msg_len-1] == L'\r' || msg[msg_len-1] == L'\n' || msg[msg_len-1] == L' ')
	{
		msg[msg_len-1] = L'\0';
		msg_len--;
	}
}

#if defined(__GNUC__)
# pragma GCC diagnostic push