服务端

网络编程中服务端接受连接的套接字创建过程如下:

1.调用socket函数创建套接字

2.调用bind函数分配IP地址和端口号

3.调用listen函数转为可接收请求状态

4.调用accept函数受理连接请求

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>          
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>void error_handing(char* messgae);void error_handing(char* message)
{fputs(message, stderr);fputc('\n', stderr);exit(1);
}int main(int argc, char*argv[])
{int serv_sock; // 服务端socketint clnt_sock;struct sockaddr_in serv_addr;struct sockaddr_in clnt_addr;char message[] = "helloworld!";if (argc != 2){printf("Usage: %s<port>\n", argv[0]);exit(1);}serv_sock = socket(PF_INET, SOCK_STREAM, 0);if (serv_sock == -1){error_handing("socket() error");}bzero(&serv_addr, sizeof(serv_addr));serv_addr.sin_family = AF_INET;serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);serv_addr.sin_port =  htons(atoi(argv[1]));if(bind(serv_sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1){error_handing("bind() error");}if(listen(serv_sock, 5) == -1){error_handing("listen() error");}socklen_t clnt_addr_len = sizeof(clnt_addr);clnt_sock = accept(serv_sock, (struct sockaddr*)&clnt_addr, &clnt_addr_len);if (clnt_sock == -1){error_handing("accept() error");}write(clnt_sock, message, sizeof(message));close(serv_sock);close(clnt_sock);return 0;
}

客户端

1.创建客户端套接字

2.连接服务端

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>          
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>void error_handing(char* messgae);void error_handing(char* message)
{fputs(message, stderr);fputc('\n', stderr);exit(1);
}int main(int argc, char*argv[])
{int sock;struct sockaddr_in serv_addr;char message[30];int str_len;if(argc != 3){printf("Usage : %s<IP><port>\n", argv[0]);exit(1);}sock = socket(PF_INET, SOCK_STREAM, 0);if(sock == -1){error_handing("socket() error");}bzero(&serv_addr, sizeof(serv_addr));serv_addr.sin_family = AF_INET;serv_addr.sin_addr.s_addr = inet_addr(argv[1]);serv_addr.sin_port = htons(atoi(argv[2]));if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1){error_handing("connect() error");}str_len = read(sock, message, sizeof(message)-1);if (str_len == -1){error_handing("read() error");}printf("message from server: %s\n", message);close(sock);return 0;
}

运行结果