Moving the kernel to modern C

Moving the kernel to modern C

In C89 and GNU89 declarations must occur before statements within each block. C89 additional requires initializers to be compiler-time constants. However, it's not as if this equivalent GNU89 code is any easier to follow:

#include <stdio.h>
#include <unistd.h>

int blah(long x, int j)
{
    long i = x ? x : -1;
    int k = i;
    {
        int i;
        for (i = 1; i < j; i++) {
            k += i * 2;
            {
                char i = (k & 1) ? 'O' : 'E';
                {
                    int pid = getpid();
                    printf("i=%d j=%d pid=%d\n", i, j, pid);
                }
            }
        }
    }
    return k;
}

The real lessons here are "use meaningful names" and "avoid shadowing".