how to force HttpQueryInfo to get "304 Not Modified" status code?

[humanista]

I have a problem with this code:

void *hInternet, *hConnect, *hRequest; 
unsigned char status_code[4], *lpBuffer; 
unsigned int dwBufferLength, dwBufferTotal, dwNumberOfBytesRead; 
hInternet = InternetOpen(0, INTERNET_OPEN_TYPE_DIRECT, 0, 0, 0); 
hConnect = InternetConnect(hInternet, "foobar2000.org", 80, 0, 0, INTERNET_SERVICE_HTTP, 0, 0); 
hRequest = HttpOpenRequest(hConnect, 0, 0, 0, 0, 0, 0, 0); 
HttpSendRequest(hRequest, 0, 0, 0, 0); 
dwBufferLength = 4; 
HttpQueryInfo(hRequest, HTTP_QUERY_STATUS_CODE, status_code, &dwBufferLength, 0); 
lpBuffer = malloc(10240); 
InternetReadFile(hRequest, lpBuffer, 10240, &dwNumberOfBytesRead); 
for(dwBufferTotal = dwNumberOfBytesRead; dwNumberOfBytesRead != 0; dwBufferTotal += dwNumberOfBytesRead) 
{ 
         InternetReadFile(hRequest, lpBuffer + dwBufferTotal, 10240 - dwBufferTotal, &dwNumberOfBytesRead); 
}
free(lpBuffer);
InternetCloseHandle(hRequest);
InternetCloseHandle(hConnect);
InternetCloseHandle(hInternet);
return;

After executing it twice, server responds with "304 Not Modified" status code, but wininet loads response from cache and HttpQueryInfo gets "200 OK". How can I force HttpQueryInfo to get real "304 Not Modified" status code?

Thanks

 

[Miros]

Can you clear the cache programatically?

 

[humanista]

Then server will responds with "200 OK" status code and that's not what I want. I want it to responds with "304 Not Modified" status code and I want HttpQueryInfo to show me this "304 Not Modified".