PVS-Studio warning V579 for Firefox

bool HTTPUpload::SendRequest(..., int *timeout, ...)
{
  if (timeout) {
    if (!InternetSetOption(request.get(),
                           INTERNET_OPTION_SEND_TIMEOUT,
                           timeout,
                           sizeof(timeout))) {
      fwprintf(stderr,
        L"Could not unset send timeout, continuing...\n");
    }
  ...
}

This suspicious code was found in Firefox project by PVS-Studio static code analyzer.
Warning message is:
V579 The InternetSetOptionW function receives the pointer and its size as arguments. It is possibly a mistake. Inspect the fourth argument. http_upload.cc 152

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/