Delete last node in singly linked list

Question

In a TED talk Linus Torvalds made a point about “good taste” at approximately 14:10 in the interview. I read through his examples of “bad taste” and “good taste” and wanted to implement the same principle for a function that deletes the last node in a singly linked list. I also followed his coding style.

#include <stdio.h>
#include <stdlib.h>

/* linked list structure */
struct node {
    int data;
    struct node *next;
};

/* create new node */
struct node *new_node(int data, struct node *next)
{
    struct node *new = malloc(sizeof *new);
    if (!new) {
        fprintf(stderr, "Error: memory allocation failed\n");
        exit(EXIT_FAILURE);
    }
    new->data = data;
    new->next = next;
    return new;
}

/* delete last node */
void delete_last(struct node *head)
{
    if (head == NULL) {
        fprintf(stderr, "Error: linked list underflow\n");
        exit(EXIT_FAILURE);
    }
    struct node **cursor = &head;
    while ((*cursor)->next != NULL)
        cursor = &(*cursor)->next;
    free(*cursor);
    *cursor = NULL;
}

Answer 1

It's quite presumptive for a function to exit the program like this:

    if (!new) {
            fprintf(stderr, "Error: memory allocation failed\n");
            exit(EXIT_FAILURE);
    }

I'd argue that the caller is also better positioned to know whether an error message is useful, too:

    if (!new) {
            return new;
    }

Similarly, removing from empty list is better conveyed by a return value.

Explicit comparison against NULL seems clunky to me (and inconsistent with the test of new above), given that pointers have a well-understood truthiness:

if (!head) {

while ((*cursor)->next)

Answer 2

I also followed [Torvalds'] coding style

I'm all for coding style standards, though I decline to listen to all of his suggestions simply because he's the loudest (seriously, very very loud) voice in the room. His blind obedience to 1988's K&R with no other rationale I find short-sighted as well. Anyway, enough editorializing:

Your non-parenthesized sizeof *new falls on a matter in his guide that is a little ambiguous -

The notable exceptions are sizeof, typeof, alignof, and __attribute__, which look somewhat like functions (and are usually used with parentheses in Linux, although they are not required in the language)

Whereas parens are not required after sizeof, I see them in the majority of code I encounter so I'd recommend sticking with them.

I warn against writing keywords from C++ as symbol names in C, in this case new. If ever you want this to be readily C++-compatible, this will cause you grief.