小弟刚学vc++这两天看pcap，老师要求自己写个明文嗅探　可我不太明白pcap里面的函数的意思，希望各位大侠能帮个忙．帮我看看下面的代码：要有好心人帮忙给个注释就好了：）谢谢
#include "pcap.h"

main()
{
pcap_if_t *alldevs;
pcap_if_t *d;
int i=0;
char errbuf[PCAP_ERRBUF_SIZE];

/* 这个API用来获得网卡 的列表 */
if (pcap_findalldevs(&alldevs, errbuf) == -1)
{
fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
exit(1);
}

/* 显示列表的响应字段的内容 */
for(d=alldevs;d;d=d->next)
{
printf("%d. %s", ++i, d->name);
if (d->description)
printf(" (%s)\n", d->description);
else printf(" (No description available)\n");
}

if(i==0)
{
printf("\nNo interfaces found! Make sure WinPcap is installed.\n");
return;
}

/* We don't need any more the device list. Free it */
pcap_freealldevs(alldevs);
}