c socket编程，一次只接收一行

Question

我的客户端一次只能接收一行。我正在尝试想出一种方法来一次接收整个流。任何人都可以纠正我关于接收问题的内容吗？我已经包含了客户端代码和我认为相关的服务器端代码的一部分。

#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>


int main(int argc, char *argv[])

{
    FILE *log;
    int opt;
    int count = 0;
    int sock, bytes_received;
    char send_data[2048],recv_data[2048];
    struct hostent *host;
    struct sockaddr_in server_addr;

    if(remove("client_log")) ;

    if(argc == 2)
    {
      if(strcmp(argv[1], "-v") == 0)
      {
        log = fopen("client_log", "a");
        opt = 1;
      }
      else if(strcmp(argv[1], "-V") == 0)
      {
        log = fopen("client_log", "a");
        opt = 2;
      }
    }

    }
    else
      opt = 0;

    host = gethostbyname("127.0.0.0");

    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("Socket");
        exit(1);
    }

    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(noneya);
    server_addr.sin_addr = *((struct in_addr *)host->h_addr);
    bzero(&(server_addr.sin_zero),8);

    if (connect(sock, (struct sockaddr *)&server_addr,
                sizeof(struct sockaddr)) == -1)
    {
        perror("Connect");
        exit(1);
    }

    while(1)
    {

      bytes_received=recv(sock,recv_data,2048,0);
      recv_data[bytes_received] = '\0';

      if (strcmp(recv_data , "q") == 0 || strcmp(recv_data , "Q") == 0)
      {
       close(sock);
       break;
      }

       else
      {
        if(opt != 0)
          fprintf(log, "\n Received Data: %s \n", recv_data);
        if(opt == 2)
          printf("\nReceived Data: %s \n" , recv_data);
      }

       if(count == 0)
       {
         printf("Pick an option: \n");
         printf("1 - to search by Department only\n");
         printf("2 - to search by Department and Class Number\n");
         printf("3 - to search more specifically\n");
         printf("q or Q - to Quit");
       }
       printf("\nSEND: ");
       gets(send_data);
       if(count == 0)
       {
         count = (int)send_data;
         if(count == 3)
            count++;
       }
       else if(count > 0)
         count--;

        if(opt != 0)
          fprintf(log, "\n Sending Data: %s \n", send_data);
        if(opt == 2)
          printf("\n Sending Data: %s \n" , send_data);

      if (strcmp(send_data , "q") != 0 && strcmp(send_data , "Q") != 0)
       send(sock,send_data,strlen(send_data), 0);

       else
      {
       send(sock,send_data,strlen(send_data), 0);
       close(sock);
       break;
      }

    }
return 0;
}

这是客户端的事情:

 case 1:

            fread(data, sizeof(sched_record), MAX_RECORD, filePointer);
            fclose(filePointer);
            char send_data[] = "Enter Department Name";
            send(connected, send_data, strlen(send_data), 0);
            bytes_received = recv(connected, recv_data, BUF, 0);
            recv_data[bytes_received] = '\0';
            strcpy(tempDept, recv_data);
            for (i=0; i<MAX_RECORD; i++){
                if ((strcmp(tempDept, data[i].Dept)==0) && tempCourse != data[i].course){
                        sprintf(send_data,"%s %d", data[i].Dept, data[i].course);
                        send(connected, send_data, strlen(send_data), 0);
                        tempCourse = data[i].course;

                }
            }
        break;

如果需要，我可以提供更多信息。我相信服务器端没问题。我使用 -Wall 和 -Wextra 进行了编译，没有收到任何警告。

Answer 1

您一次接收一行数据，因为一次发送一行数据。不过，它最终以这种方式出现的事实纯属运气； TCP 流可以由客户端 TCP 堆栈或通过另一端的缓冲任意拆分和重新组合。您需要在流中使用某种形式的显式框架——例如，在每行之前发送一个计数，或在一行末尾发送一个 \n。