在backlog=0的情况下,客户机为什么不拒绝连接?

我在玩Linux域套接字,现在我谈到了关于理解backlog的问题。以下是服务器端代码:

const char *const hostname = "/tmp/test_local_addr";

int sock_fd = socket(AF_LOCAL, SOCK_STREAM, 0);

struct sockaddr_un server_address;
memset(&server_address, '\0', sizeof(struct sockaddr_un));
server_address.sun_family = AF_LOCAL;
strncpy(server_address.sun_path, hostname, hostname_len + 1);
const socklen_t addrlen = offsetof(struct sockaddr_un, sun_path) + hostname_len + 1;

bind(sock_fd, (struct sockaddr*) &server_address, addrlen);

int listen_result = listen(sock_fd, 0);

我将待办事项的大小设置为 0 在听的时候不要打电话 accept connect . 但当我跑的时候 strace nc -U /tmp/test_local_addr 从两个不同的终端我有第一个打印

connect(3, {sa_family=AF_UNIX, sun_path="/tmp/test_local_addr"}, 110) = 0
poll([{fd=0, events=POLLIN}, {fd=3, events=0}, {fd=3, events=POLLIN}, {fd=1, events=0}], 4, -1

第二个呢

--- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} ---
connect(3, {sa_family=AF_UNIX, sun_path="/tmp/test_local_addr"}, 110

我不太清楚这种行为。我以为他们两个都会立即终止 Connection refused

read(-1, 0x7fffc0db3740, 16384)         = -1 EBADF (Bad file descriptor)

只有在我终止服务器时才会在两个客户端中发生。