URLdownloadToFileW Doesn't download a file [duplicate] - c++

Question

I'm new to c++ and try to write a update function.
The download with URLDownloadToFile is working without problems but if I changed the url to an invalid one, it stilled return S_OK ... How can I check if the download succede or not?
#include <WinInet.h>
#include <iomanip>
int download_file (const TCHAR urldownload[],const TCHAR target[] )
{
DownloadProgress progress;
IBindStatusCallback* callback = (IBindStatusCallback*)&progress;
SCP(40, NULL); cout << target;
HRESULT status = URLDownloadToFile(NULL, urldownload, target, 0, static_cast<IBindStatusCallback*>(&progress));
Sleep(200);
DeleteUrlCacheEntry(urldownload);
wcout << status;
if (status == S_OK) cout << "yes";
else(cout << "Download failed");
Sleep(10000); return 1;
}
class DownloadProgress : public IBindStatusCallback {
public:
HRESULT __stdcall QueryInterface(const IID &, void **) {
return E_NOINTERFACE;
}
ULONG STDMETHODCALLTYPE AddRef(void) {
return 1;
}
ULONG STDMETHODCALLTYPE Release(void) {
return 1;
}
HRESULT STDMETHODCALLTYPE OnStartBinding(DWORD dwReserved, IBinding *pib) {
return E_NOTIMPL;
}
virtual HRESULT STDMETHODCALLTYPE GetPriority(LONG *pnPriority) {
return E_NOTIMPL;
}
virtual HRESULT STDMETHODCALLTYPE OnLowResource(DWORD reserved) {
return S_OK;
}
virtual HRESULT STDMETHODCALLTYPE OnStopBinding(HRESULT hresult, LPCWSTR szError) {
return E_NOTIMPL;
}
virtual HRESULT STDMETHODCALLTYPE GetBindInfo(DWORD *grfBINDF, BINDINFO *pbindinfo) {
return E_NOTIMPL;
}
virtual HRESULT STDMETHODCALLTYPE OnDataAvailable(DWORD grfBSCF, DWORD dwSize, FORMATETC *pformatetc, STGMEDIUM *pstgmed) {
return E_NOTIMPL;
}
virtual HRESULT STDMETHODCALLTYPE OnObjectAvailable(REFIID riid, IUnknown *punk) {
return E_NOTIMPL;
}
virtual HRESULT __stdcall OnProgress(ULONG ulProgress, ULONG ulProgressMax, ULONG ulStatusCode, LPCWSTR szStatusText)
{
//wcout << ulProgress << L" of " << ulProgressMax << endl; Sleep(200);
if (ulProgress != 0 && ulProgressMax != 0)
{
double output = (double(ulProgress) / ulProgressMax)*100;
cout << "\r" << "Downloading: " << fixed << setprecision(2) << output << " % " ; Sleep(20);
}
return S_OK;
}
};

Answer 1

MSDN article has the answer for you:
URLDownloadToFile returns S_OK even if the file cannot be created and the download is canceled. If the szFileName parameter contains a file path, ensure that the destination directory exists before calling URLDownloadToFile. For best control over the download and its progress, an IBindStatusCallback interface is recommended.
You need to provide a status callback to receive status of the asynchronous operation. Your code snippet already has the base. OnProgress and OnStopBinding should get you the download failure result.