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POAdding an int member to a C struct causes a segfault
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copied!<p>I'm still learning C, and have started using it to generate images. I can't figure out why one of my programs is segfaulting. Here's the source code, cut down to 40 lines:</p> <pre><code>#include <stdio.h> #include <stdlib.h> struct color { unsigned char r, g, b; }; struct image { int w, h/*, o*/; struct color **data; }; int main() { // Declarations int x, y; struct color *black; struct image *img; // Set up color black black = (struct color *) malloc(sizeof(struct color *)); black->r = 0; black->g = 0; black->b = 0; // Set up image img img = (struct image *) malloc(sizeof(struct image *)); img->w = 1; img->h = 1; /*img->o = 0;*/ img->data = (struct color **) malloc(img->h * sizeof(struct color *)); for (y = 0; y < img->h; y++) { img->data[y] = (struct color *) malloc(img->w * sizeof(struct color)); } // Fill in img with black for (x = 0; x < img->w; x++) { for (y = 0; y < img->h; y++) { img->data[y][x].r = black->r; img->data[y][x].g = black->g; img->data[y][x].b = black->b; } } // Free black free(black); // Free img for (y = 0; y < img->h; y++) free(img->data[y]); free(img->data); // Segfaults free(img); // Also segfaults return 0; } </code></pre> <p>It compiles and runs fine (using gcc on Ubuntu and on Vista with Cygwin), but uncommenting the two lines dealing with img->o breaks it. I have a feeling it's related to <a href="https://stackoverflow.com/questions/433700/segfault-from-adding-a-variable">this previous question</a>, but I'm malloc'ing everything that needs to be malloc'ed (I think). Any help would be appreciated.</p>

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