Hi Daniel,
                   Thanks for your response,
I have tried all following option and it doesn't seems to work for me.
                      //pHeader=curl_slist_append(pHeader,"Pragma: no-cache"); // Option 1
                pHeader=curl_slist_append(pHeader,"Cache-Control: no-cache"); // Option 2
                //pHeader=curl_slist_append(pHeader,"Cache-Control: must-revalidate"); // Option 3
                //pHeader=curl_slist_append(pHeader,"Cache-Control: max-age=0"); // Option 4
                //pHeader=curl_slist_append(pHeader,"Expires: Thu, 01 Dec 1994 16:00:00 GMT"); // Option 5
                curl_easy_setopt(handle,CURLOPT_HTTPHEADER,pHeader);

First Attempt : Tried only option 1
Second Attempt : Tried option 1 + Option 2
Third Attempt : Tried option 1 + Option 2 + Option 5
Fourth Attempt : Tried only option 3
fifth Attempt : Tried only option 4

but none of these seems to have worked ,
I saw one more post http://curl.haxx.se/mail/lib-2005-04/0022.html
But it seems I have already tried all these options.

I have monitored my network traffic using the "Microsoft Network Monitor 3.4"
And I see the http request packet ,
ProtocolVersion is HTTP/1.1
and there then I see all the headers that I have set Pragma, ChacheControl, Expires etc.
since ProtocolVersion is HHTP/1.1 ChacheControl should have worked ideally isn't it?

Is there anything that I am still missing.
-Arif

------------------------------

Message: 2
Date: Wed, 11 Jan 2012 13:56:28 +0100 (CET)
From: Daniel Stenberg <daniel_at_haxx.se>
To: libcurl development <curl-library_at_cool.haxx.se>
Subject: Re: Query regarding the caching problem faced with curl
        7.19.3, how to disable cache usage ?
Message-ID: <alpine.DEB.2.00.1201111354220.17896_at_tvnag.unkk.fr>
Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII

On Wed, 11 Jan 2012, Arif Ali Saiyed wrote:

> my problem is even after the file is being updated on web server, It's
> still downloading the cached copy of it.

This is not due to any caching done by curl though, as curl has no caching of contents at all - ever.

> after some search I found that there is something called "Pragma:nochache"
> header, but I am not sure how to use this ? there is no
> curl_easy_setopt for doing this.

You insert that header into a request by yourself with CURLOPT_HTTPHEADER. See http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTHTTPHEADER

-- 
  / daniel.haxx.se
----------------------------------------------------------------------
Message: 1
Date: Wed, 11 Jan 2012 18:10:31 +0530
From: Arif Ali Saiyed <asaiyed_at_adobe.com>
To: "curl-users_at_cool.haxx.se" <curl-users_at_cool.haxx.se>,
	"curl-library_at_cool.haxx.se" <curl-library_at_cool.haxx.se>
Subject: Query regarding the caching problem faced with curl 7.19.3,
	how to	disable cache usage ?
Message-ID:
	<B815C26F687D26448A336840033924ED420332970E_at_INDIAMBX01.corp.adobe.com>
Content-Type: text/plain; charset="us-ascii"
Hi There,
                   I am using curl 7.19.3 in my C++ code.
My code fetches some http file,  my problem is even after the file is being updated on web server, It's still downloading the cached copy of it.
I want to know how to disable this behavior I have tried following easy set option but it did not work me
           curl_easy_setopt(handle, CURLOPT_FRESH_CONNECT, 1);        // I guess this has got nothing to do with cache but still I tried and it did not help
           curl_easy_setopt(handle, CURLOPT_FORBID_REUSE, 1);         // I guess this has got nothing to do with cache but still I tried and it did not help
           curl_easy_setopt(handle, CURLOPT_SSL_SESSIONID_CACHE, 0);  // I guess this has got nothing to do with cache but still I tried and it did not help
after some search I found that there is something called "Pragma:nochache" header, but I am not sure how to use this ? there is no curl_easy_setopt for doing this.
Though its not needed following is the  codesnippet of how I am using curl
     CURL* handle = curl_easy_init();
     CURLcode err = CURLE_READ_ERROR;
     if(handle)
     {
           currentStatus = kInitiated;
           curl_easy_setopt(handle, CURLOPT_URL, myFileName);
           curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, my_write_data_handler);
           err = curl_easy_perform(handle);
           curl_easy_cleanup(handle);
           curl_global_cleanup();
           currentStatus = kCompleted;
     }
-asaiyed
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