如何发送和接收数据套接字TCP(C/C++)

Question

可能重复:
在C/C++中从TCP套接字读取的正确方法是什么？

我正在尝试开发TCP客户端/服务器.我的问题是,当我尝试从客户端发送数据时,我会在一次发送中执行此操作.

但是当我尝试接收具有特定结构的数据时出现我的问题,我的意思是,前8个字节设置日期,接下来的10个名称和未定义的字节数设置文本(此文本以/ r/n结尾)/R/N)

客户端发送如下:

char date[8];
char name[10];
char msg[4096];

strcpy(msg,"12/10/12"); //8 bytes
strcat(msg,"Kevin Fire"); //10 bytes
strcat(msg,"abcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcde\r\n\r\n");

nbytes_sent = send(sock,(char *)msg,sizeof(msg),0);
printf("Bytes_sent: %s -> %i\n",msg,nbytes_sent);

并且服务器尝试从socket解析数据,如下所示:

char date[8];
char name[10];
char * text;
char buf[1024];

int i=0;
for(i=0; i < 8; i++)
    date[i] = '\0';
for(i=0; i < 10; i++)
    name[i] = '\0';

nbytes_read=recv(sclient,(char *)date,sizeof(date),0);
if(nbytes_read > 0){
    printf("Date: %s (%i)\n",date,nbytes_read);
    //cout.flush();
    nbytes_read=recv(sclient,(char *)name,sizeof(name),0);
    if(nbytes_read > 0){
        printf("Name: %s (%i)\n",name,nbytes_read);
        //cout.flush();
        nbytes_read=recv(sclient,(char *)buf,sizeof(buf),0);
        strcpy(text,buf);
        while(nbytes_read > 0){
            nbytes_read=recv(sclient(char*)buf,sizeof(buf),0);
            strcat(text,buf);
        }
    }
}

printf("Date: %s. Name: %s. Text: %s\n",date,name,text);

Answer 1

这是一个简单的"全部接收"功能:

int recv_all(int sockfd, void *buf, size_t len, int flags)
{
    size_t toread = len;
    char  *bufptr = (char*) buf;

    while (toread > 0)
    {
        ssize_t rsz = recv(sockfd, bufptr, toread, flags);
        if (rsz <= 0)
            return rsz;  /* Error or other end closed cnnection */

        toread -= rsz;  /* Read less next time */
        bufptr += rsz;  /* Next buffer position to read into */
    }

    return len;
}