from Hacker News

Linked lists in C, with open source ADT

by AncoraImparo on 1/20/13, 1:26 AM with 38 comments

• by AncoraImparo on 1/20/13, 2:49 AM

  Sorry for posting this, it appears that HN is not the place to post content if your only goal is to help people to learn. The hacker ethic is dead I guess, Richard Stallman really was the last man standing then. Remind me to come and post something when I decide to make some silly iPhone / android app when I want to make money rather than sharing knowledge.

  Thanks.

• by gosu on 1/20/13, 2:30 AM

  This isn't how I'd do a linked list in C. Having to malloc separate storage for the next/prev pointers imposes a big cost in terms of performance (it's hardly O(1)) and robustness. Your linked list operations can all fail now - sooner or later, that's going to put you in a very tight spot.

  I prefer to store next/prev pointers with the data itself, and to use offsetof/containerof to find a pointer to the data struct which contains a given set of next/prev pointers.

  One example of such an scheme is the list used in the Linux kernel:

  http://lxr.linux.no/#linux+v3.7.3/include/linux/list.h

  http://lwn.net/Articles/336255/

• by tptacek on 1/20/13, 2:10 AM

  The book _C Interfaces and Implementation_ is nothing but library interfaces like this and their implementations.

  You are, for whatever it's worth, better off defaulting to a variable-length array than to a linked list.

• by chj on 1/20/13, 2:26 AM

  Some simple suggestions:

  1. Please align the asterisks properly. It hurts eyes.

  2. Access by index?

  3. Iterator (callback on each element)

  4. use 'init' instead of 'initialize'. Extra typing hurts fingers.

• by afhof on 1/20/13, 2:10 AM

  On the front page, "test.c" is listed twice. Should it be "list.c" ?

• by categorykni on 1/20/13, 1:30 AM

  This is week-one stuff of a CS degree or on the job training. If you don't know this you shouldn't be programming.