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POStrange backtrace - where is the error?
 

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  1. POStrange backtrace - where is the error?
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    <p>I'm developing an image processing application in C++. I've seen a lot of compiler errors and backtraces, but this one is new to me. </p> <pre><code>#0 0xb80c5430 in __kernel_vsyscall () #1 0xb7d1b6d0 in raise () from /lib/tls/i686/cmov/libc.so.6 #2 0xb7d1d098 in abort () from /lib/tls/i686/cmov/libc.so.6 #3 0xb7d5924d in ?? () from /lib/tls/i686/cmov/libc.so.6 #4 0xb7d62276 in ?? () from /lib/tls/i686/cmov/libc.so.6 #5 0xb7d639c5 in malloc () from /lib/tls/i686/cmov/libc.so.6 #6 0xb7f42f47 in operator new () from /usr/lib/libstdc++.so.6 #7 0x0805bd20 in Image&lt;Color&gt;::fft (this=0xb467640) at ../image_processing/image.cpp:545 </code></pre> <p>What's happening here? The operator new is crashing, ok. But why? That's not an out of memory (it tries to allocate about 128Kb, a 128x64 pixel with two floats each). Also, it doesn't seam as it's an error in my own code (the constructor doesn't get touched!). </p> <p>The code in the mentioned line (#7) is:</p> <pre><code>Image&lt;Complex&gt; *result = new Image&lt;Complex&gt;(this-&gt;resX, resY); // this-&gt;resX = 128, resY = 64 (both int), Complex is a typedef for std::complex&lt;float&gt; </code></pre> <p>Almost the same instantiation works on other places in my code. If I comment out this part of the code, it will crash a bit later on a similar part. I don't understand it, I also don't have any ideas, how to debug it. Any help?</p> <p>Compiler is gcc 4.3.3, libc is 2.9 (both from Ubuntu Jaunty) </p> <p><strong>Update:</strong></p> <p>I've included the following lines just above the faulty line in the same method and in main()</p> <pre><code> Image&lt;Complex&gt; *test = new Image&lt;Complex&gt;(128, 64); delete test; </code></pre> <p>The strange thing: in the same method it will crash, in main() it won't. As I mentioned, Complex is a typedef of std::complex&lt;float&gt;. The constructor doesn't get called, I've inserted a cout just before this line and in the constructor itself.</p> <p><strong>Update 2:</strong></p> <p>Thanks to KPexEA for this tip! I tried this:</p> <pre><code>Image&lt;Complex&gt; *test = new Image&lt;Complex&gt;(128, 64); delete test; kiss_fft_cpx *output = (kiss_fft_cpx*) malloc( this-&gt;resX * this-&gt;resY/2 * sizeof(kiss_fft_cpx) ); kiss_fftndr( cfg, input, output ); Image&lt;Complex&gt; *test2 = new Image&lt;Complex&gt;(128, 64); delete test2; </code></pre> <p>It crashes at - you guess? - test2! So the malloc for my kissfft seams to be the faulty one. I'll take a look at it.</p> <p><strong>Final update:</strong></p> <p>Ok, it's done! Thanks to all of you! </p> <p>Actually, I should have noticed it before. Last week, I noticed, that kissfft (a fast fourier transform library) made a 130x64 pixel fft image from a 128x128 pixel source image. Yes, 130 pixel broad, not 128. Don't ask me why, I don't know! So, 130x64x2xsizeof(float) bytes had to be allocated, not 128x64x... as I thought before. Strange, that it didn't crash just after I fixed that bug, but some days later. </p> <p>For the record, my final code is:</p> <pre><code>int resY = (int) ceil(this-&gt;resY/2); kiss_fft_cpx *output = (kiss_fft_cpx*) malloc( (this-&gt;resX+2) * resY * sizeof(kiss_fft_cpx) ); kiss_fftndr( cfg, input, output ); Image&lt;Complex&gt; *result = new Image&lt;Complex&gt;(this-&gt;resX, resY); </code></pre> <p>Thanks!</p> <p>craesh</p>
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    1. COPerhaps add an example of the "almost the same" instantiation that works?
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