Can't get InternetReadFile to work

[paprica]

Hello, here's my code:

std::string ReadHTML()
{
	BYTE buf = 0;
	DWORD dwRead;

	std::string s = "";

	while(InternetReadFile(m_hOpenURL, reinterpret_cast<LPVOID>(buf), 1, &dwRead) == TRUE)
	{
		if(dwRead == 0) 
			break;

		s += buf;
	}

	return s;
}

What am I doing wrong?

[VladimirF]

std::string ReadHTML()
{
	BYTE buf = 0;
	DWORD dwRead;

	while(InternetReadFile(m_hOpenURL, reinterpret_cast<LPVOID>(buf), 1, &dwRead) == TRUE)
	{
}

What am I doing wrong?

The second parameter should be "Pointer to a buffer that receives the data."
You pass a value of 0, forcefully casted to LPVOID.
My guess is - access violation writing to 0x00000000.

[paprica]

You're right. Thanks!

InternetReadFile(m_hOpenURL, &buf, 1, &dwRead)

[Igor Vartanov]

The snipped is from a real code:

    TCHAR buf[4096];
    DWORD dwRead = 0;
    while( ::InternetReadFile( hInetUrl, buf, sizeof(buf), &dwRead ) && (dwRead != 0) )
    {
      DWORD dwWritten = 0;
      if( ::WriteFile( hFile, buf, dwRead, &dwWritten, NULL ) )
      {
        ATLASSERT( dwRead == dwWritten );
        qwYield += dwRead;
        PutYield( qwYield );
        if( qwTotal && (QWORD(-1) != qwTotal) )
        {
          // move progress safely
          PutProgress( 100 * DOUBLE(qwYield)/qwTotal );
        }
      }
      else
      {
        throw(ERR_TARGET_WRITE_FAIL); // write file failed
      }																	 
    }