Debenu Quick PDF Library - PDF SDK Community Forum : RenderPageToString: How to free result memory http://www.quickpdf.org/forum/ Copyright (c) 2006-2013 Web Wiz Forums - All Rights Reserved. Fri, 01 May 2026 05:16:48 +0000 Wed, 21 Aug 2013 15:40:01 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 11.01 360 www.quickpdf.org/forum/RSS_post_feed.asp?TID=2702 <![CDATA[Debenu Quick PDF Library - PDF SDK Community Forum]]> http://www.quickpdf.org/forum/forum_images/QPDF_Forum_Title.png http://www.quickpdf.org/forum/ <![CDATA[RenderPageToString: How to free result memory : tfrost wrote:Allocating and...]]> http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11129.html#11129 Author: kmsb12
Subject: 2702
Posted: 21 Aug 13 at 3:40PM

Originally posted by tfrost tfrost wrote:

Allocating and freeing memory on opposite sides of a DLL boundary is normally a recipe for subtle problems

To clearify, I do not delete the memory block holding the pixel data directly. I tried that too, but it did not work Wink
Instead I delete the whole library object.

DebenuPDFLibraryDLL0914 *pdfLib = new DebenuPDFLibraryDLL0914(...);
...
// do whatever with pdfLib
...
delete pdfLib;

By doing this, I have to recreate the library object again every time after destroying it. But that's OK. As I use the DA... (direct access) methods, I do not need to reload the whole PDF file as I instantiate the pdf library.
]]> Wed, 21 Aug 2013 15:40:01 +0000 http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11129.html#11129 <![CDATA[RenderPageToString: How to free result memory : Are you absolutely certain that...]]> http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11127.html#11127 Author: tfrost
Subject: 2702
Posted: 21 Aug 13 at 10:51AM

Are you absolutely certain that your main program and the DLL use a common allocator and common memory pools, and always will in future?  Allocating and freeing memory on opposite sides of a DLL boundary is normally a recipe for subtle problems which hit you long after the event, when the pool is next used.]]> Wed, 21 Aug 2013 10:51:19 +0000 http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11127.html#11127 <![CDATA[RenderPageToString: How to free result memory : Thanks for your answers!QP.LibraryVersion...]]> http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11122.html#11122 Author: kmsb12
Subject: 2702
Posted: 20 Aug 13 at 4:25PM

Thanks for your answers!
QP.LibraryVersion did not work for me.
I now free the library with delete (I am using the C++ wrapper of the library)


]]> Tue, 20 Aug 2013 16:25:55 +0000 http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11122.html#11122 <![CDATA[RenderPageToString: How to free result memory : Kristoff,DQPL maintains a buffer...]]> http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11069.html#11069 Author: AndrewC
Subject: 2702
Posted: 06 Aug 13 at 4:33AM

Kristoff,

DQPL maintains a buffer to return data from the DLL.  As you have correctly determined the memory is not freed again until the next call to the DLL.  You could call something like QP.LibraryVersion which will return a much much smaller buffer effectively freeing the larger buffer from the previous DLL call.

Andrew.
]]> Tue, 06 Aug 2013 04:33:35 +0000 http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11069.html#11069 <![CDATA[RenderPageToString: How to free result memory : Hi Kristoff!I think you&#039;ll...]]> http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11065.html#11065 Author: Ingo
Subject: 2702
Posted: 05 Aug 13 at 6:33PM

Hi Kristoff!

I think you'll need the FREE ;-)
Another hint: Don't mix (never!) DA... and non-DA-functions!
Inside a try...create...finally...free...end you should use DA... or non-DA but never both!
This you can read in the online-references, too ;-)

Cheers and welcome here,
Ingo

]]> Mon, 05 Aug 2013 18:33:36 +0000 http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11065.html#11065 <![CDATA[RenderPageToString: How to free result memory : I am using the RenderPageToString...]]> http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11064.html#11064 Author: kmsb12
Subject: 2702
Posted: 05 Aug 13 at 2:16PM

I am using the RenderPageToString and the DARenderPageToString functions of the Quickpdf library.
Those functions return me a pointer to char (char*) to the rendering results. The memory holding the result data will not be freed until I call RenderPageToString again. The memory will not be cleaned up when I call DACloseFile either.
I found out that I can call DARenderPageToString with an invalid pageRef (0 for instance). The memory from the last rendered page is cleaned up and no new memory will be reserved for the next page rendering.

My question now: Is there any official function for cleaning up memory and invalidating the render results or do I have to live with my workaround?

Thanks a lot.
Kristoff


]]> Mon, 05 Aug 2013 14:16:07 +0000 http://www.quickpdf.org/forum/renderpagetostring-how-to-free-result-memory_topic2702_post11064.html#11064