unix下 socket用到了哪几个头文件?

fan2290

#include<sys/types.h>
#include<netinet/in.h>

if( (sock =socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0 )
        {
                printf("connect failed.\n");
        }

我这样写 提示说 socket未定义.

albcamus

man 2 socket