服务端代码：

#include <stdio.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<string.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include <unistd.h>
#include<errno.h>/*
socket
bind
listen
accept
send/receive
*/
#define SOCKET_PORT 8888
#define SOCKET_BACKLOG 10int main(int argc, char **argv)
{char  *errStr;int iSocketSever;struct sockaddr_in tSocketSeverAddress;struct sockaddr_in tSocketClientAddress;int iRet;int iClientSocket;int iAddrLen;int iRecvLen;unsigned char ucReceiveBuffer[1000];int iClientNumber = -1;    iSocketSever = socket(AF_INET, SOCK_STREAM, 0);if (iSocketSever < 0){printf("socket error\n");}tSocketSeverAddress.sin_family = AF_INET;tSocketSeverAddress.sin_port = htons(SOCKET_PORT);// host to network address,short porttSocketSeverAddress.sin_addr.s_addr = INADDR_ANY;//本机所有IPmemset(tSocketSeverAddress.sin_zero , 0, 8);iRet = bind(iSocketSever, ( struct sockaddr *)&tSocketSeverAddress, sizeof(struct sockaddr));if (iRet == -1){errStr = (char*)strerror(errno);printf("bind error, errno = %d\n",errno);printf("bind error, error = %s\n",errStr);return -1;}iRet = listen(iSocketSever, SOCKET_BACKLOG);if (iRet == -1){printf("listen error\n");return -1;}while (1){iAddrLen = sizeof(struct sockaddr); //iClientSocket = accept(iSocketSever, (struct sockaddr *)&tSocketClientAddress,&iAddrLen);if (iClientSocket != -1){iClientNumber ++;printf("connect success,from client %d: %s\n", iClientNumber, inet_ntoa(tSocketClientAddress.sin_addr));if (!fork()){/*子进程的源码*/while (1){/* 接受客户端发来的数据并显示出来 */iRecvLen = recv(iClientSocket, ucReceiveBuffer,999,0);if (iRecvLen <= 0){close(iClientSocket);return -1;}else{   ucReceiveBuffer[iRecvLen+1] = '\0';printf("get msg from client %d: %s\n", iClientNumber, ucReceiveBuffer);}}}}}close(iSocketSever);return 0;
}

获取errno错误码：

函数原型：char *strerror(int errnum);

通过标准错误的编号errno，获得错误的描述字符串；

方便用户查找，返回值是指向错误信息的指针。

#include<errno.h>

#include<string.h>

char *errStr;

errStr = (char*)strerror(errno);

printf("bind error, error = %s\n",errStr);

客户端代码：

#include <stdio.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<string.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include <unistd.h>/*
socket
connect
send/recva
*/
#define SOCKET_PORT 8888int main(int argc, char **argv)
{int iClientSocket;struct sockaddr_in tSocketSeverAddress;int iRet;   unsigned char ucSendBuffer[1000];int iSendLen;if (argc != 2) {printf("usage: \n");printf("%s <server_ip>\n", argv[0]);return -1;}iClientSocket = socket(AF_INET, SOCK_STREAM, 0);tSocketSeverAddress.sin_family = AF_INET;tSocketSeverAddress.sin_port = htons(SOCKET_PORT);if ( inet_aton(argv[1],&tSocketSeverAddress.sin_addr) == 0 ){printf("invalid server IP \n");return -1;}memset(tSocketSeverAddress.sin_zero , 0, 8);iRet = connect(iClientSocket, (struct sockaddr *)&tSocketSeverAddress, sizeof(tSocketSeverAddress));if ( iRet == -1 ){printf("connect failed\n");}while (1){if (fgets(ucSendBuffer,999,stdin)){iSendLen = send(iClientSocket, &ucSendBuffer ,strlen(ucSendBuffer),0);if ( iSendLen < 0){close(iClientSocket);return -1;}}}return 0;
}