inet_ntoa在64位机器上出错

inet_ntoa用法如下：

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char *inet_ntoa(struct in_addr in);
就是将struct in_addr结构转换为IP地址的形式，struct in_addr这个结构应该不陌生吧，它的定义如下：

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struct in_addr{
       unsigned long s_addr;
}
struct sockaddr_in {
       short int sin_family;
       unsigned short int sin_port;
       struct in_addr sin_addr;
       unsigned char sin_zero[8];
};
在服务器端使用accept函数之后，会得到客户端连接的struct sockaddr结构，然后将其转换成struct sockaddr_in结构，此时可以在服务器端得到客户端连接的IP和端口数据。

这时用这个函数有一个问题是：如果在64位的机器上，使用

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char* tmp = inet_ntoa(sin->sin_addr);
之后，对tmp进行操作，会出现断错误，但在32位机器上没有问题，原因是64位时inet_ntoa返回值是一个整型。
在网上找的两种解决办法：

在使用的文件中，引用#include <arpa/inet.h>头文件。
直接使用inet_ntop函数。
inet_ntop的说明如下：

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NAME
       inet_ntop - Parse network address structures

SYNOPSIS
       #include <sys/types.h>
       #include <sys/socket.h>
       #include <arpa/inet.h>

       const char *inet_ntop(int af, const void *src,
                             char *dst, socklen_t cnt);

DESCRIPTION
       This function converts the network address structure src in the af address family into a char-
       acter string, which is copied to a character buffer dst, which is cnt bytes long.

       inet_ntop(3) extends the inet_ntoa(3) function to support multiple   address   families,
       inet_ntoa(3) is now considered to be deprecated in favor of inet_ntop(3). The following
       address families are currently supported:

       AF_INET
              src points to a struct in_addr (network byte order format) which is converted to an IPv4
              network address in the dotted-quad format, "ddd.ddd.ddd.ddd". The buffer dst must be at
              least INET_ADDRSTRLEN bytes long.

       AF_INET6
              src points to a struct in6_addr (network byte order format) which is converted to a rep-
              resentation of this address in the most appropriate IPv6 network address format for this
              address. The buffer dst must be at least INET6_ADDRSTRLEN bytes long.

RETURN VALUE
       inet_ntop() returns a non-null pointer to dst. NULL is returned if there was an error, with
       errno set to EAFNOSUPPORT if af was not set to a valid address family, or to ENOSPC if the con-
       verted address string would exceed the size of dst given by the cnt argument.

CONFORMING TO
       POSIX.1-2001. Note that RFC 2553 defines a prototype where the last parameter cnt is of type
       size_t. Many systems follow RFC 2553. Glibc 2.0 and 2.1 have size_t, but 2.2 has socklen_t.

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