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如何在 C 创建 UDP 服务器?
原标题:How to create a UDP server in C?

我试图在 C (Linux) 中写入 UDP 服务器。 我知道在 socket () 函数中,我必须使用 SOCK_DGRAM 而不是 SOCK_STREAM

if ( (list_s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0 ) 
{
    fprintf(stderr, "ERROR");
}

但现在,当我尝试运行程序( 编译中没有错误) 时, 它表示 < code> listen () < () 中存在错误。 以下是调用 :

if (listen(list_s, 5) < 0)
{
    fprintf(stderr, "ERROR IN LISTEN");
    exit(EXIT_FAILURE);
}

你能找出问题所在吗?

int       list_s;                /*  listening socket          */
int       conn_s;                /*  connection socket         */
short int port;                  /*  port number               */
struct    sockaddr_in servaddr;  /*  socket address structure  */

if ( (list_s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0 ) 
{
    fprintf(stderr, "ERROR
");
}

memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family      = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port        = htons(port);

if ( bind(list_s, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0 )
{
    fprintf(stderr, "ERROR IN BIND 
");
}

if ( listen(list_s, 5) < 0 )      // AL POSTO DI 5 LISTENQ
{
    fprintf(stderr, "ERROR IN LISTEN
");
    exit(EXIT_FAILURE);
}
最佳回答

您不能在数据格套接字上 < code> listen 上输入数据格套接字, 它只是没有定义。 您只需要使用 < code> > bind 并开始循环阅读 。

作为简短解释, listen 通知操作系统,它应该期待该套接头上的 connection ,而且您以后会接受。显然,这对数据格插座没有意义,因此是错误的。


侧边注意 : 您应该尝试使用 < code>perror 打印这种错误。 在这种情况下, 它( 可能) 会说 < em> Operation 不支持

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