隐式转换是什么错误
//这是lunix下的传输数据的客户端
#include<stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define SERVPORT 3333
#define MAXDATASIZE 100 /*每次最大数据传输量 */
main(int argc, char *argv[]){
int sockfd, recvbytes;
char buf[MAXDATASIZE];
struct hostent *host;
struct sockaddr_in serv_addr;
if (argc < 2) {
fprintf(stderr,"Please enter the server's hostname!\n");
exit(1);
}
if((host=gethostbyname(argv[1]))==NULL) {
herror("gethostbyname出错！");
exit(1);
}
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){
perror("socket创建出错！");
exit(1);
}
serv_addr.sin_family=AF_INET;
serv_addr.sin_port=htons(SERVPORT);
serv_addr.sin_addr = *((struct in_addr *)host->h_addr);
bzero(&(serv_addr.sin_zero),8);
if (connect(sockfd, (struct sockaddr *)&serv_addr, \
sizeof(struct sockaddr)) == -1) {
perror("connect出错！");
exit(1);
}
if ((recvbytes=recv(sockfd, buf, MAXDATASIZE, 0)) ==-1) {
perror("recv出错！");
exit(1);
}
buf[recvbytes] = '\0';
printf("Received: %s",buf);
close(sockfd); //这一句报错了，说是“隐式声明函数”。这是怎么回事？怎样修改呢？
}
[解决办法]
#include <unistd.h>
