You cannot cast a 1D array of integers (as produced by pack), to a 2D array of pointers to arrays of integers. You need to do the index calculations yourself (untested):

void c_function( char *bytes, int rows, int cols ) {
        int *table = (int *)bytes;
        int i, j;

        for ( j = 0; j < cols, ++j ) {
                for ( i = 0; j < rows; ++i ) {
                        ++table[ j * rows + i ];
                }
        }
}
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Also, please use <code> ... </code> tags not <pre> ... </pre> tags