Conflicting types error in C after using prototype

Question

I try to run an example code in K&R (p30) using Xcode. I got conflicting types error for 'getline' and when I call getline, I was informed that I should pass 3 arguments to it, instead of 2. I'm confused.

#include <stdio.h>
#define MAXLINE 1000 /* maximum input line length */

int getline(char line[], int maxline);
void copy(char to[], char from[]);

/* print the longest input line */
int main()
{
    int len; /* current line length */
    int max; /* maximum length seen so far */
    char line[MAXLINE]; /* current input line */
    char longest[MAXLINE]; /* longest line saved here */

    max = 0;
    while ((len = getline(line[MAXLINE], MAXLINE)) > 0)
        if (len > max) {
            max = len;
            copy(longest, line);
        }
    if (max > 0) /* there was a line */
        printf("%s", longest);
    return 0;
}

/* getline: read a line into s, return length */
int getline(char s[],int lim)
{
    int c, i;

    for (i=0; i < lim-1 && (c=getchar())!=EOF && c!='\n'; ++i)
        s[i] = c;
    if (c == '\n') {
        s[i] = c;
        ++i;
    }
    s[i] = '\0';
    return i;
}

/* copy: copy 'from' into 'to'; assume to is big enough */
void copy(char to[], char from[])
{
    int i;

    i = 0;
    while ((to[i] = from[i]) != '\0')
        ++i;
}

Answer 1

Since K&R was written, POSIX has added a function getline() which has a different interface from the one in K&R:

ssize_t getline(char **restrict lineptr, size_t *restrict n, FILE *restrict stream);

The only reasonable way around it is to rename the function in the code copied from the book.

(It was a nuisance when it was added — I'd used a variant on the K&R code for 20+ years, but there's no point in fighting it.)