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POc free pointer to structure
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copied!<p>I'm writing in plain C and I have an issue about how to free a pointer to a structure. I have a structure declared in the following way</p> <pre><code>typedef struct _RealMatrix { uint nRows; uint nCols; real **matrix; } RealMatrix; </code></pre> <p>Now, every time I need it I use the following code to allocate it</p> <pre><code>RealMatrix *realMatrixAlloc(uint n, uint m) { loop_var(i); RealMatrix *matrix; matrix = malloc(sizeof(RealMatrix)); errcheck(matrix, "Unable to create real matrix structure."); matrix->nRows = n; matrix->nCols = m; matrix->matrix = malloc(n*sizeof(real *)); matrix->matrix[0] = malloc(n*m*sizeof(real)); errcheck(matrix->matrix && matrix->matrix[0], "Unable to get requested memory for real matrix of dimensions: (%u, %u).", n, m); f_i(i < n) matrix->matrix[i] = matrix->matrix[0] + i*m; return matrix; } </code></pre> <p>where errcheck() is a allocation checking macro. Everything works just fine until I try to deallocate it calling</p> <pre><code>freeRealMatrix(&myRealMatrix); </code></pre> <p>which will</p> <pre><code>free((*ma)->matrix[0]), free((*ma)->matrix) free(*ma). *ma = NULL; </code></pre> <p>with suitable checks to avoid following any NULL pointer. Here "ma" is the pointer TO THE POINTER to the structure: the function declaration reads</p> <pre><code>void freeRealMatrix(RealMatrix **ma); </code></pre> <p>However when this function returns I find out that "myRealMatrix" is still addressing an existing structure, which was not deallocated as I expected by free(*ma). On the other hand the array (*ma)->matrix has been successfully deallocated.</p> <p>Any ideas about what am I doing wrong? This is driving me crazy... Thanks in advance!</p> <p>UPDATE:</p> <p>I copied the code and executed in a brand new program... It works precisely as expected. I noticed that the address contained in "myRealMatrix" isn't the same as the address pointed by *ma. Well... Sort of: it seems truncated! Instead of being 0x106a50 it is just 0x106a and no more. The last two hex digits are missing every time!</p>

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