UrlToDownloadFile function not downloading - c++

Question

I am using UrlToDownloadFile function, but it doesn't download the file. No error shown in compiler (using VStudio 2012)
Here is the code:
#include <Windows.h>
#include "urlmon.h"
#pragma lib "urlmon.lib"
using namespace std;
void dwFile();
int _tmain(int argc, _TCHAR* argv[])
{
dwFile ();
return 0;
}
void dwFile ()
{
LPCSTR url = ("http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf");
LPCSTR fPath = ("C:\\Users\\Andyy\\Desktop\\test\\n3337.pdf");
HRESULT URLDownloadToFile ((NULL, url, fPath, 0, NULL));
}

Answer 1

Your code is not doing any error handling, and your string handling is wrong. Use this instead:
#include <Windows.h>
#include "urlmon.h"
#pragma lib "urlmon.lib"
using namespace std;
void dwFile();
int _tmain(int argc, _TCHAR* argv[])
{
dwFile ();
return 0;
}
void dwFile ()
{
LPCTSTR url = TEXT("http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf");
LPCTSTR fPath = TEXT("C:\\Users\\Andyy\\Desktop\\test\\n3337.pdf");
HRESULT hr = URLDownloadToFile (NULL, url, fPath, 0, NULL);
if (FAILED(hr))
{
// do something ...
}
/* or more preffered:
LPCWSTR url = L"http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf";
LPCWSTR fPath = L"C:\\Users\\Andyy\\Desktop\\test\\n3337.pdf");
HRESULT hr = URLDownloadToFileW (NULL, url, fPath, 0, NULL);
if (FAILED(hr))
{
// do something ...
}
*/
}
Do note the following comment in the documentation:
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.