利用不定长的结构体发送socket数据

//Server端代码

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<sys/types.h>#include<netinet/in.h>#include<sys/socket.h>#include<unistd.h>//使用不定长的结构体发送数据的关键在于：结构体变量必须分配到堆中，而不是栈中//即只能用malloc或者new来给结构体分配空间typedef struct Node{int nodeSize;int bufSize;char buf[0];             //用0字节表示该结构体不定长} Node;int main(){int sockfd,new_fd;struct sockaddr_in server_addr;struct sockaddr_in client_addr;if((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1){printf("socket error!\n");exit(1);}server_addr.sin_family = AF_INET;server_addr.sin_port = htons(5050);server_addr.sin_addr.s_addr = INADDR_ANY;bzero(&(server_addr.sin_zero),8);if(bind(sockfd,(struct sockaddr *)&server_addr,sizeof(server_addr)) == -1){printf("bind error!\n");exit(1);}if(listen(sockfd,100) == -1){printf("listen error!\n");exit(1);}printf("Server is listening:\n");while(1){int sin_size = sizeof(struct sockaddr_in);if((new_fd = accept(sockfd,(struct sockaddr *)&client_addr,(socklen_t *)&sin_size)) == -1){printf("accept error!\n");exit(1);}int recvSize = 0;//data total lengthif(recv(new_fd,(char *)&recvSize,sizeof(recvSize),0) == -1){printf("recv error!\n");exit(1);}int leftSize = sizeof(char) * (recvSize - sizeof(int));char *dataBuf = (char *)malloc(leftSize);memset(dataBuf,0,leftSize);if(recv(new_fd,dataBuf,leftSize,0) == -1){printf("recv error!\n");exit(1);}close(new_fd);Node *p = (Node *)malloc(sizeof(char) * recvSize);p->nodeSize = recvSize;memcpy((char *)(&p->bufSize),dataBuf,leftSize);printf("nodeSize = %d\n",p->nodeSize);printf("bufSize = %d\n",p->bufSize);printf("buf = %s\n",p->buf);}return 0;}

//Client端代码

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<sys/types.h>#include<arpa/inet.h>#include<netinet/in.h>#include<sys/socket.h>#include<unistd.h>typedef struct Node{int nodeSize;int bufSize;char buf[0];} Node;int main(){int sockfd,new_fd;struct sockaddr_in server_addr;if((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1){printf("socket error!\n");exit(1);}server_addr.sin_family = AF_INET;server_addr.sin_port = htons(5050);server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");bzero(&(server_addr.sin_zero),8);if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof(server_addr)) == -1){printf("connect error!\n");exit(1);}printf("Client is connecting\n");const char *tmp = "this is a test!";int tmpLen = strlen(tmp);Node *dataBuf = (Node *)malloc(sizeof(Node) + tmpLen + 1);dataBuf->nodeSize = sizeof(Node) + tmpLen + 1;dataBuf->bufSize = tmpLen;memset(dataBuf->buf,0,tmpLen + 1);memcpy(dataBuf->buf,tmp,tmpLen + 1);printf("nodeSize = %d\n",dataBuf->nodeSize);printf("bufSize = %d\n",dataBuf->bufSize);printf("buf = %s\n",dataBuf->buf);if(send(sockfd,(char *)dataBuf,dataBuf->nodeSize,0) == -1){printf("send error!\n");exit(1);}close(sockfd);return 0;}