Not sure what the return value of Inet_pton in PHP is? How to solve it

Not sure what the return value of Inet_pton in PHP is?
I see a document saying that Inet_pton's features are:
Converts a human readable IP address to its packed IN_ADDR representation
The return value is:
Returns the in_addr representation of the given address.
What is packed in_addr representation?
How do I remove the return value or display the return value?
Why I echo,print_r out the content is all garbled.
Var_dump came out of the
String (16) "@"
String (16) "?"
String (16) "0"
String (16) "0"
String (16) "0@"
String (16) "0?"
These things

------Solution--------------------
Note: This function is not implemented under the Windows platform.


------Solution--------------------
IN_ADDR is a struct, binary, no need to display
------Solution--------------------
The big-endian byte stream of IP.

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