# RMagick: UnableToConcatenateString \` **URL:** \ **Category:** Ruby\ **Created:** [September 4, 2007, 8:42am UTC](https://www.ruby-forum.com/t/rmagick-unabletoconcatenatestring/113712 "2007-09-04T08:42:56Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![jonathan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/aeb1de/32.png) [@jonathan](https://www.ruby-forum.com/u/jonathan)\ **Post date:** [September 4, 2007, 8:42am UTC](https://www.ruby-forum.com/t/rmagick-unabletoconcatenatestring/113712/1 "2007-09-04T08:42:56Z")
I have a program to generate my website bluebottleimages.org It creates thumbnails using Rmagick. I run the program (on the server), and it goes for a while, but then I get RMagick: UnableToConcatenateString ` '. Warning: recursive semaphore lock detected! and it’s stopped there. It has come up invariably at the same spot, so I thought it was corrupted image files, but even after replacing them I get the error message. Now I’m thinking that it’s probably just that I’m over-using server resources making all those thumbnails… Do you think that’s the case, or is it more likely that there’s a problem with my program? If you like I can post my code. ---
**Author:** ![jonathan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/aeb1de/32.png) [@jonathan](https://www.ruby-forum.com/u/jonathan)\ **Post date:** [September 4, 2007, 1:21pm UTC](https://www.ruby-forum.com/t/rmagick-unabletoconcatenatestring/113712/2 "2007-09-04T13:21:48Z")
Jonathan D. wrote: > and it’s stopped there. > > It has come up invariably at the same spot, so I thought it was > corrupted image files, but even after replacing them I get the error > message. Now I’m thinking that it’s probably just that I’m over-using > server resources making all those thumbnails… Do you think that’s > the case, or is it more likely that there’s a problem with my program? > > If you like I can post my code. Try adding a periodic call to GC.start to your program. See this note: [http://rubyforge.org/forum/forum.php?thread\_id=1374&forum\_id=1618](http://rubyforge.org/forum/forum.php?thread_id=1374&forum_id=1618) ---
**Author:** ![jonathan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/aeb1de/32.png) [@jonathan](https://www.ruby-forum.com/u/jonathan)\ **Post date:** [September 4, 2007, 7:25pm UTC](https://www.ruby-forum.com/t/rmagick-unabletoconcatenatestring/113712/3 "2007-09-04T19:25:33Z")
Tim H. wrote: > Try adding a periodic call to GC.start to your program. See this note: > [http://rubyforge.org/forum/forum.php?thread\_id=1374&forum\_id=1618](http://rubyforge.org/forum/forum.php?thread_id=1374&forum_id=1618) Thanks! It works perfectly now ---
**Author:** ![jonathan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/aeb1de/32.png) [@jonathan](https://www.ruby-forum.com/u/jonathan)\ **Post date:** [September 4, 2007, 7:39pm UTC](https://www.ruby-forum.com/t/rmagick-unabletoconcatenatestring/113712/4 "2007-09-04T19:39:14Z")
Tim H. wrote: > used by individual image objects with the Magick::Image#destroy! method, > thus eliminating the need to call GC.start from time to time. Seems like ruby could help out libraries like RMagick by exposing an API to tell GC that memory has been allocated by something other than ruby’s malloc. Did anyone ever pursue that? ---
**Author:** ![jonathan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/aeb1de/32.png) [@jonathan](https://www.ruby-forum.com/u/jonathan)\ **Post date:** [September 4, 2007, 7:30pm UTC](https://www.ruby-forum.com/t/rmagick-unabletoconcatenatestring/113712/5 "2007-09-04T19:30:38Z")
Jonathan D. wrote: > Tim H. wrote: > > > Try adding a periodic call to GC.start to your program. See this note: > > [http://rubyforge.org/forum/forum.php?thread\_id=1374&forum\_id=1618](http://rubyforge.org/forum/forum.php?thread_id=1374&forum_id=1618) > > Thanks! It works perfectly now Good news! Looking forward, starting with RMagick 2.0.0 you can free the memory used by individual image objects with the Magick::Image#destroy! method, thus eliminating the need to call GC.start from time to time. ---
**Author:** ![jonathan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/aeb1de/32.png) [@jonathan](https://www.ruby-forum.com/u/jonathan)\ **Post date:** [September 4, 2007, 9:37pm UTC](https://www.ruby-forum.com/t/rmagick-unabletoconcatenatestring/113712/6 "2007-09-04T21:37:56Z")
Joel VanderWerf wrote: > Tim H. wrote: > > > used by individual image objects with the Magick::Image#destroy! method, > > thus eliminating the need to call GC.start from time to time. > > Seems like ruby could help out libraries like RMagick by exposing an API > to tell GC that memory has been allocated by something other than ruby’s > malloc. Did anyone ever pursue that? This may help in the general case but for RMagick not so much. RMagick doesn’t know how much memory ImageMagick is allocating for an image. Even if it knew or could compute the amount of the initial allocation the amount of memory used for an image can vary over the lifetime of the image. I suppose RMagick could give Ruby an estimate, which might help some. I gave some thought to trying to get ImageMagick to use Ruby’s memory management API. It seems like it might solve the problem, but I’m not sure that the IM developers would want to devote that much effort to Ruby users. Adding #destroy! is something I could do on my own. It more-or-less parallels the way you can close files and sockets and otherwise free up resources that Ruby either doesn’t know about or might let hang around longer than necessary.