Gets a socket option. These are protocol and system specific, see your local system documentation for details. The option is returned as a Socket::Option object.
Parameters
-
level
is an integer, usually one of the SOL_ constants such as Socket::SOL_SOCKET, or a protocol level. A string or symbol of the name, possibly without prefix, is also accepted. -
optname
is an integer, usually one of the SO_ constants, such as Socket::SO_REUSEADDR. A string or symbol of the name, possibly without prefix, is also accepted.
Examples
Some socket options are integers with boolean values, in this case getsockopt could be called like this:
reuseaddr = sock.getsockopt(:SOCKET, :REUSEADDR).bool optval = sock.getsockopt(Socket::SOL_SOCKET,Socket::SO_REUSEADDR) optval = optval.unpack "i" reuseaddr = optval[0] == 0 ? false : true
Some socket options are integers with numeric values, in this case getsockopt could be called like this:
ipttl = sock.getsockopt(:IP, :TTL).int optval = sock.getsockopt(Socket::IPPROTO_IP, Socket::IP_TTL) ipttl = optval.unpack("i")[0]
Option values may be structs. Decoding them can be complex as it involves examining your system headers to determine the correct definition. An example is a +struct linger+, which may be defined in your system headers as:
struct linger { int l_onoff; int l_linger; };
In this case getsockopt could be called like this:
# Socket::Option knows linger structure. onoff, linger = sock.getsockopt(:SOCKET, :LINGER).linger optval = sock.getsockopt(Socket::SOL_SOCKET, Socket::SO_LINGER) onoff, linger = optval.unpack "ii" onoff = onoff == 0 ? false : true
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