Question 16.8

What do ``Segmentation violation'' and ``Bus error'' mean?

These generally mean that your program tried to access memory it shouldn't have, invariably as a result of improper pointer use. Likely causes are inadvertent use of null pointers (see also questions 5.2 and 5.20) or uninitialized, misaligned, or otherwise improperly allocated pointers (see questions 7.1 and 7.2); corruption of the malloc arena (see question 7.19); and mismatched function arguments, especially involving pointers; two possibilities are scanf (see question 12.12) and fprintf (make sure it receives its first FILE * argument).