#define PTR_TO_GID(p) ((gid_t) (((uintptr_t) (p))-1))
#define GID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))
+#define PTR_TO_PID(p) ((pid_t) ((uintptr_t) p))
+#define PID_TO_PTR(p) ((void*) ((uintptr_t) p))
+
#define memzero(x,l) (memset((x), 0, (l)))
#define zero(x) (memzero(&(x), sizeof(x)))