问个比较小白的问题：listnode *createlist(listnode *h)是什么意思？ 定义函数不是 int或void+ 函数名

#include <stdio.h>
#include <stdlib.h>
struct node{
int num;
struct node *next;
};
typedef struct node listnode;
listnode *createlist(listnode *h)
{
listnode *p,*q;
int i,n;
scanf( "%d", &n );
for ( i = 0; i < n; i++ )
{
p = (listnode *)malloc(sizeof(listnode));
scanf( "%d", &p->num );
if ( i == 0 )
{
h = p;
}
else
{
q->next = p;
}
q = p;
}
q->next = NULL;
return h;
}
void traverselist(listnode *h)
{
listnode *p = h;
while( p != NULL )
{
printf( "%d ", p->num );
p = p->next;
}
printf( "\n" );
}
int main()
{
listnode *head;
head = createlist(head);
traverselist(head);
return 0;
}

相关了解……