Generic list manipulation function in C?

Question

What is a generic list manipulation function in C? (I saw this when I was going through some materials.)

What is the difference between this function and a function

Answer 1

For my teachings I came to develop this "generic" list module, probably a simplify version of the linux kernel one, with additional though undiscovered bugs included, and that uses gcc extensions... Any comments are welcomed !

#ifndef _LISTE
#define _LISTE
#include 
typedef struct liste_s {
  struct liste_s * suivant ;
} * liste ;


#define newl(t) ( (liste) malloc ( sizeof ( struct liste_s ) + sizeof ( t ) ) )
#define elt(l,t) ( * ( ( t * ) ( l + 1 ) ) )

#define liste_vide NULL
#define videp(l) ( l == liste_vide )
#define lvide() liste_vide
#define cons(e,l) \
  ({ liste res = newl(typeof(e)) ;      \
     res->suivant = l ; \
     elt(res,typeof(e)) = e ;           \
    res ; }) 

#define hd(l,t) ({ liste res = l ; if ( videp(res) ) exit ( EXIT_FAILURE ) ; elt(res,t) ; })
#define tl(l)   ({ liste res = l ; if ( videp(res) ) exit ( EXIT_FAILURE ) ; res->suivant ;})


#endif