Author: Julia Lawall <julia@diku.dk> In each case, the print involves dereferencing a value that is NULL or is near NULL. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @r exists@ expression E,E1; identifier f; statement S1,S2,S3; @@ if ((E == NULL && …) || …) { … …