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POSegmentation fault by writing in a 2D Array
 

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    <p>I have a small memory access problem in my program and I do not find the error, maybe someone could help me. </p> <p>I have created a new type to store rgb color values. That type looks like:</p> <pre><code>typedef struct pixel { unsigned char r; unsigned char g; unsigned char b; } pixel; </code></pre> <p>In my main program I create with calloc a 2D dynamically array, to store the red color information’s.</p> <pre><code>pixel **pixelvalue = (pixel **) calloc(imginformation.width, sizeof(pixel)); for (i = 0; i &lt; imginformation.width; i++) { pixelvalue[i] = (pixel *) calloc(imginformation.height, sizeof(pixel)); } </code></pre> <p>After that I call my function, which read the color values and who should safe them to the array. The function gets as parameter the array.</p> <pre><code>ReadFile(file, imginformation (Stuff like height and so one), pixelvalue (The calloc array)); </code></pre> <p>In that function I try to write the values with </p> <pre><code>pixelvalue[i][j].r = (unsigned char)fgetc(in); </code></pre> <p>Here I get the memory access error, what did I wrong?</p> <p><strong>Edit</strong></p> <p>Hi, first of all sorry about the missing language, I was a little bit tired yesterday :).</p> <p>To understanding, I created an array of pixel and the elements are pointing to another array of pixel? Something like <code>[Point to another 1D array pixel]</code>?</p> <p>With pixel <code>**pixelvalue = calloc(imginformation.width, sizeof(pixel *));</code> I create <code>imginformation.width</code> numbers of pointers from type pixel and each pointer show to pixel, right?</p> <p>It would be awesome if you could explain it a little bit more, if I’m wrong. I would really like to understand it. </p> <p>@carl-norum What do you mean with:</p> <blockquote> <p>"you shouldn't be casting the return values of calloc(). Doing so can hide bugs with #include that could come back to bite you down the road". </p> </blockquote> <p>? I use the alloc space as parameter for a function, not as return value.</p> <p>Thanks for your help!</p> <p>Greetz</p>
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