如何在Unix套接字编程中获取本地IP地址和端口？ [英] How to get local IP address and port in Unix socket programming?

问题描述

我用它作为创建新服务器的地址（ socket（）， bind（）， listen（））：

I used this as the address to create a new server(socket(), bind(), listen()):

struct sockaddr_in newServer;
memset(&newServer, 0, sizeof(newServer));
newServer.sin_family = AF_INET;
newServer.sin_addr.s_addr = htonl(INADDR_ANY);
newServer.sin_port = htons(UNUSED_PORT);

宏UNUSED_PORT定义为0.

The macro UNUSED_PORT is defined as 0.

我希望服务器能够监听任何接口和未使用的端口。

I expect to get a server listening on any interface and on an unused port.

我试图使用 getsockname（）获取我的本地IP地址和端口，但我得到了一些奇怪的输出。输出代码如下：

I tried to use getsockname() to get my local IP address and port, but I got some strange outputs. The output code as below:

struct sockaddr_in localAddress;
socklen_t addressLength;
getsockname(newServerfd, (struct sockaddr*)&localAddress,   \
                &addressLength);
printf("local address: %s\n", inet_ntoa( localAddress.sin_addr));
printf("local port: %d\n", (int) ntohs(localAddress.sin_port));

例如，我得到0.255.255.255：0,0.0.0.0：0,255.127.0.0： 36237等等
我的系统是Mac OS X 10.7.3。

For example, I got 0.255.255.255:0, 0.0.0.0:0, 255.127.0.0:36237, etc. and my system is Mac OS X 10.7.3.

- 更新 -

使用 socklen_t addressLength = sizeof（localAddress）; （感谢@cnicutar和@Jonathan Leffler），我总是得到0.0.0.0的本地IP;可以吗？

After using socklen_t addressLength = sizeof(localAddress); (thanks to @cnicutar and @Jonathan Leffler), I always get 0.0.0.0 for local IP; is that all right?

推荐答案

你需要在调用之前初始化 addressLength getsockname ：

You need to initialize addressLength before calling getsockname:

socklen_t addressLength = sizeof(localAddress);

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