链表操作，获得泛型效果

http://stackoverflow.com/questions/2583580/what-is-the-best-way-to-write-class-template-like-generic-code-in-c

struct list_element_s{
void* data;
struct list_element_s next;
};
typedef struct list_element_s list_element;
struct list_s
{
void (*destructor)(void* data);
int  (*com)(const void *src,const void* dest);
unsigned int size;
list_elememt *head; 
list_element  * tail;
};
typedef struct list_s  list;
list *list_alloc(void(*destructor)(void* data));//alloc memory for the list
int list_free(list* l);//free the alloced memory
int list_insert(list* l,list_element*  element,const void* data);//insert notes
void* list_remove_next(list* l,list_element * element);//remove notes
list* list_alloc(void(*destructor)(void* data))
{
list* h=NULL;
if(h=calloc(1,sizeof(*l)))!=NULL){
h->size=0;
h->destructor=destructor;
h->head=NULL;
h->tail=NULL;
}
return h;
}

int list_free(list* h)
{
void *data;
if(h=NULL||h->destructor=NULL){
return -1;
}
while(h->size>0)
{
if(data=list_remove_next(1,NULL))!=NULL){
list->destructor(data);
}
free(h);
return 0;
}
}

int list_insert_next(list* h,list_element* element,const void* data)
{
list_element* new=NULL;
new=calloc(1,sizeof(*new));
if(h==NULL||new==NULL){
return -1;
}
new->data=(void*)data;
new->next=NULL;
if(NULL==element)
{
if(h->size==0)
h->tail=new;
new->next=h->head;
h->head=new;
}
else{
if(element->next==NULL) h->tial=new;
new->next=element->next;
element->next=new;
}
h->size++;
return 0;
}

void *list_remove_next(list* h,list_element* element)
{
void* data=NULL;
list_element *old==NULL;
if(h==NULL||h->size==0){
return NULL;
}
if(element==NULL){
data=h->data;
old=l->head;
h->head=h->head->next;
if(h->size==1){
h->tail=NULL;
}
}
else{
if(element->next=NULL){
return NULL;
}
data=element->next->data;
old=element->next;
element->next=old->next;
if(element->next==NULL)
h->tail=element;
}
}
free(old);
l->size--;
return data;
}

#include <stdlib.h> 
#include <stdio.h> 
//#include "nmlist.h" 
 
void simple_free(void *data){ 
    free(data); 
} 
 
int main(int argc, char *argv[]){ 
    list *l = NULL; 
    int i, *j; 
 
    l = list_alloc(simple_free); 
    for(i = 0; i < 10; i++){ 
        j = calloc(1, sizeof(*j)); 
        if(j != NULL){ 
            *j = i; 
            list_insert_next(l, NULL, (void*) j); 
        } 
    } 
 
    for(i = 0; i < 10; i++){ 
        j = (int*) list_remove_next(l, NULL); 
        if(j != NULL){ 
            printf("%d \n", *j); 
        } 
    } 
 
    list_free(l); 
 
    return (0); 
} 

};