[英]strange error when using printf and inet_ntoa to print ip address
struct in_addr a,b,c,d;
if(inet_aton ("10.0.0.1", &a)!=-1 );
printf("a:%s\n", inet_ntoa(a));
if(inet_aton ("10.0.0.2", &b)!=-1 )
printf("b:%s\n", inet_ntoa(b));
It's no problem to print the to IP address: 打印到IP地址没有问题:
a:10.0.0.1
b:10.0.0.2
However I found that: 但是我发现:
inet_aton ("10.0.0.3", &c);
inet_aton ("10.0.0.4", &d);
printf("c:%s %s\n", inet_ntoa(c), inet_ntoa(d));
printf("d:%s\n", inet_ntoa(d));
It prints: 它打印:
c:10.0.0.3 d:10.0.0.3
d:10.0.0.4
The strange things is that it prints the wrong IP of d
at this line: 奇怪的是,它在此行打印了错误的
d
IP:
printf("c:%s %s\n", inet_ntoa(c), inet_ntoa(d));
I don't know why! 我不知道为什么!
The manual for inet_ntoa
says: inet_ntoa
的手册说:
The string is returned in a statically allocated buffer, which subsequent calls will overwrite.
该字符串在静态分配的缓冲区中返回,后续调用将覆盖该缓冲区。
You have two functions in printf("c:%s %s\\n", inet_ntoa(c), inet_ntoa(d));
在
printf("c:%s %s\\n", inet_ntoa(c), inet_ntoa(d));
有两个函数printf("c:%s %s\\n", inet_ntoa(c), inet_ntoa(d));
that overwrite the same buffer. 覆盖相同的缓冲区。
Try if (inet_ntoa(c) == inet_ntoa(d))
, you may be surprised by the result. 尝试
if (inet_ntoa(c) == inet_ntoa(d))
,您可能会对结果感到惊讶。
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