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Filename : setsockopt-i.yaml
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--- !ruby/object:RI::MethodDescription 
aliases: []

block_params: 
comment: 
- !ruby/struct:SM::Flow::P 
  body: Sets a socket option. These are protocol and system specific, see your local sytem documentation for details.
- !ruby/struct:SM::Flow::H 
  level: 3
  text: Parameters
- !ruby/object:SM::Flow::LIST 
  contents: 
  - !ruby/struct:SM::Flow::LI 
    label: "*"
    body: <tt>level</tt> is an integer, usually one of the SOL_ constants such as Socket::SOL_SOCKET, or a protocol level.
  - !ruby/struct:SM::Flow::LI 
    label: "*"
    body: <tt>optname</tt> is an integer, usually one of the SO_ constants, such as Socket::SO_REUSEADDR.
  - !ruby/struct:SM::Flow::LI 
    label: "*"
    body: "<tt>optval</tt> is the value of the option, it is passed to the underlying setsockopt() as a pointer to a certain number of bytes. How this is done depends on the type:"
  - !ruby/object:SM::Flow::LIST 
    contents: 
    - !ruby/struct:SM::Flow::LI 
      label: "-"
      body: "Fixnum: value is assigned to an int, and a pointer to the int is passed, with length of sizeof(int)."
    - !ruby/struct:SM::Flow::LI 
      label: "-"
      body: "true or false: 1 or 0 (respectively) is assigned to an int, and the int is passed as for a Fixnum. Note that <tt>false</tt> must be passed, not <tt>nil</tt>."
    - !ruby/struct:SM::Flow::LI 
      label: "-"
      body: "String: the string's data and length is passed to the socket."
    type: :BULLET
  type: :BULLET
- !ruby/struct:SM::Flow::H 
  level: 3
  text: Examples
- !ruby/struct:SM::Flow::P 
  body: "Some socket options are integers with boolean values, in this case #setsockopt could be called like this:"
- !ruby/struct:SM::Flow::VERB 
  body: "  sock.setsockopt(Socket::SOL_SOCKET,Socket::SO_REUSEADDR, true)\n"
- !ruby/struct:SM::Flow::P 
  body: "Some socket options are integers with numeric values, in this case #setsockopt could be called like this:"
- !ruby/struct:SM::Flow::VERB 
  body: "  sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_TTL, 255)\n"
- !ruby/struct:SM::Flow::P 
  body: "Option values may be structs. Passing them can be complex as it involves examining your system headers to determine the correct definition. An example is an <tt>ip_mreq</tt>, which may be defined in your system headers as:"
- !ruby/struct:SM::Flow::VERB 
  body: "  struct ip_mreq {\n    struct  in_addr imr_multiaddr;\n    struct  in_addr imr_interface;\n  };\n"
- !ruby/struct:SM::Flow::P 
  body: "In this case #setsockopt could be called like this:"
- !ruby/struct:SM::Flow::VERB 
  body: "  optval =  IPAddr.new(&quot;224.0.0.251&quot;) + Socket::INADDR_ANY\n  sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, optval)\n"
full_name: BasicSocket#setsockopt
is_singleton: false
name: setsockopt
params: " setsockopt(level, optname, optval)\n"
visibility: public