enum { SIZE = 510, THRESHOLD  = 16 } ;
typedef unsigned char *string ;
typedef struct { string *sa; int sn, si; } stack_t ;
void  simplesort  (string*, int, int) ;

static void  rsorta(string *a, int n, int b)
    {
#   define  push(a, n, i)   sp->sa = a, sp->sn = n, (sp++)->si = i
#   define  pop(a, n, i)    a = (--sp)->sa, n = sp->sn, i = sp->si
#   define  stackempty()    (sp <= stack)
#   define  swap(p, q, r)   r = p, p = q, q = r

    stack_t     stack[SIZE], *sp = stack, stmp, *oldsp, *bigsp ;
    string      *pile[256], *ak, *an, r, t ;
    static int  count[256], cmin, nc ;
    int         *cp, c, cmax /*, b = 0*/ ;
    
    push(a, n, b) ;
    while( !stackempty()) {
        pop(a, n, b) ;
        if(n < THRESHOLD) {             /* divert */
            simplesort(a, n, b) ;
            continue ;
        }
        an = a + n ;
        if(nc == 0) {                   /* untallied? */
            cmin = 255 ;                /* tally */
            for(ak = a; ak < an; ) {
                c = (*ak++)[b] ;
                if(++count[c] == 1 && c > 0) {
                    if(c < cmin) cmin = c ;
                    nc++ ;
                }
            }
            if(sp+nc > stack+SIZE) {    /*  stack overflow */ 
                rsorta(a, n, b) ;
                continue ;
            }
        }
        oldsp = bigsp = sp, c = 2 ;     /* logarithmic stack */
        pile[0] = ak = a+count[cmax=0]; /* fínd places */
        for(cp = count+cmin; nc > 0; cp++, nc--) {
            while(*cp == 0) cp++ ;
            if(*cp > 1) {
                if(*cp > c) c = *cp, bigsp = sp ;
                push(ak, *cp, b+1) ;
            }
            pile[cmax = cp-count] = ak += *cp ;
        }
        swap(*oldsp, *bigsp, stmp) ;
        an -= count[cmax] ;             /* permute home */
        count[cmax] = 0 ;
        for(ak = a; ak < an; ak += count[c], count[c]  = 0) {
            r = *ak ;
            while(--pile[c = r[b]] > ak)
                swap(*pile[c], r, t) ;
            *ak = r ;
        }                   /* here nc = count[...] = 0 */
    }
}

void rsort(string *a, int n) { rsorta(a, n, 0); }

In function `_start':
undefined reference to `main'
In function `rsorta':
undefined reference to `simplesort'