From Forum Nokia Wiki

The getpeername method gets name of connected peer socket.

int getpeername (int s, struct sockaddr * restrict name, socklen_t * restrict namelen);

The getpeername system call returns the name of the peer connected to socket s. The namelen argument should be initialized to indicate the amount of space pointed to by name. On return it contains the actual size of the name returned (in bytes). The name is truncated if the buffer provided is too small.

Following code snippet shows the usage of getpeername method:

#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
void GetSockName()
{
   int sock_fd;
   int newsock_fd;
   struct sockaddr_in addr;
   struct sockaddr_in ss;
   struct sockaddr_in new_socket;
   unsigned int len;
   unsigned int addr_len;
    
   sock_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
       
   addr.sin_family = AF_INET;
   addr.sin_addr.s_addr = htonl(INADDR_ANY);
   addr.sin_port = htons(5000);
   bind(sock_fd,(struct sockaddr*)&addr,sizeof(addr));
   listen(sock_fd,1);
   newsock_fd = accept(sock_fd,(struct sockaddr*)&new_socket,&addr_len); // Code blocks here
  
   // Assuming client has connected to the server. 
   len = sizeof(ss);
   getpeername(sock_fd,(struct sockaddr*)&ss,&len);
   close(newsock_fd);
   close(sock_fd);
 }

Wiki Links

Open C Sockets Overview