Recv() returns 正确的长度但不要复制消息

Question

我有下一个代码：

while(1) {
    int length=sizeof(client);
    connSock=accept(readSock, (struct sockaddr*) &client,&length);
    if(!fork()) 
    {
        close(readSock);
        char receiveBuff[1000],sendBuff[1000];
        int status;
        int size_buf;
        do {
            status=recv(connSock, receiveBuff, 1000,0);
            printf("%d status \n",status);
            printf("%s recv buff\n", receiveBuff);
            memcpy(sendBuff,receiveBuff,sizeof(receiveBuff));
            send(connSock, &sendBuff, sizeof(sendBuff), 0);

        }while (status!=0);
        close(connSock);
        exit(0);
    }
    close(connSock);
}

我正在尝试发送消息 "Test" 和 recv() 函数 returns 4（正确的长度），但是当我尝试打印 receiveBuffer 它时不起作用。这是输出：

4 status 
h: recv buff

这是客户端的代码：

void Client_Connector::Start_Connection()
{
    this->sock=socket(AF_INET,SOCK_STREAM,0);
    bzero(&this->server,sizeof(server));
    this->server.sin_family=AF_INET;
    inet_pton(AF_INET,"127.0.0.1", &this->server.sin_addr);
    server.sin_port=htons(2500);
    int status=connect(sock,(struct sockaddr*) &server, sizeof(server));
    if (status==0)
        cout<<"Sunteti conectat! \n";
    else
        Eroare("Eroare de conexiune! Conexiunea nu s-a putut realiza.");
}
    
void Client_Connector::send_Buffer(char* sendMessage)
{
    int i;
    i=send(sock, &sendMessage,strlen(sendMessage)+1,0);
    cout<<i<<endl;
}

然后调用函数：

connecter.Start_Connection();
string sendmsg("Test");
sendmsg+="[=14=]";
connecter.send_Buffer((char*)sendmsg.c_str());

Answer 1

问题是你实际上并没有发送字符串，而是将指针发送到字符串：

i=send(sock, &sendMessage,strlen(sendMessage),0);

此处&sendMessage将是指向变量sendMessage的指针，而不是指向字符串第一个字符的指针。

简单的解决方案：

i = send(sock, sendMessage, strlen(sendMessage) + 1, 0);

这将发送实际的字符串内容，包括终止空字符。

我还建议您退后几步，刷新您对数组和指针以及相关运算符的了解。

Recv() returns 正确的长度但不要复制消息

Recv() returns the correct lenght but don't copy the message

c

sockets

server