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target_alloc(3) 		  Arcan Lua API 		 target_alloc(3)

NAME
     target_alloc - Bind an external connection point or force-push a subsegment

SYNOPSIS
     vid:new_vid, aid:new_aid, int:new_cookie
     target_alloc( string:cpoint, function:callback )
     target_alloc( string:cpoint, string:passkey, function:callback )
     target_alloc(  string:cpoint,  string:passkey, int:w, int:h, function:call-
     back )
     target_alloc( string:cpoint, int:w, int:h, function:callback )
     target_alloc( vid:fsrv )
     target_alloc( vid:fsrv, function:callback )
     target_alloc( vid:fsrv, int:w, int:h, function:callback )
     target_alloc( vid:fsrv, function:callback, string:type )
     target_alloc( vid:fsrv, function:callback, number:tag )
     target_alloc( vid:fsrv, int:w, int:h, function:callback, string:type )
     target_alloc(  vid:fsrv,  int:w,  int:h,  function:callback,   string:type,
     bool:forced )

DESCRIPTION
     This  functions  controls	server-side  initiated allocation of segments or
     connection points. If the initial argument is of the cpoint  form, the  al-
     location will be a named connection point to which a client can connect. If
     the  initial  argument is of the fsrv  form, a subsegment will be allocated
     and pushed to the client. This form is more specialised and intended  as  a
     server-side  means  of  requesting and probing for client- side support for
     alternate views of whatever the fsrv  connection current presents. This can
     be further specified by providing a type  (debug, accessibility) and  if  a
     backend  implementation  should  be forced or not (default=false). The form
     and use for callback  is the same as in launch_target  ,  please  refer  to
     that  function for detailed documentation. The optional passkey  form is an
     aditional authentication string that the connecting client is  expected  to
     be  able  to authenticate against in a platform defined function, typically
     as a simple string comparison or challenge-response and is not intended  as
     a strong means of authentication. For such cases, the launch_target  mecha-
     nism  combined with the target/configuration database is preferred, as only
     the connection itself will be authenticated, the contents can still be sub-
     ject to interception and tampering by a local attacker.

NOTES
     1	    To push new output segments, see define_recordtarget ,  define_null-
	    target  and define_feedtarget .

     2	    Each  call	that allows a non-authoritative connection is only valid
	    once, if a connection fail to verify OR  a connection is  completed,
	    the connection point will be removed.

     3	    The  connection  key  is  limited  to 30 characters from the set [a-
	    Z,_0-9] and the actual search path / mechanism is implementation de-
	    fined.

     4	    The first example below will continuously listen for new connections
	    under the 'nonauth' key. In a real-world setting,  be  sure  to  re-
	    strict the number of allowed connections to avoid running out of re-
	    sources  and to monitor for suspicious activities e.g. a high amount
	    of connections or connection attempts in a short timeframe etc.

     5	    The connection point is consumed (closed, unlinked) when  the  first
	    verified  connection  goes	through. To re-use the connection point,
	    invoke target_alloc again with the same key from within the callback
	    handler.

     6	    for honoring explicit requests from a frameserver regarding new sub-
	    segments, use the accept_target function.

     7	    When a 'connected' event has been received, many applications expect
	    a displayhint event before being able to proceed  (with  information
	    about the current surface dimensions and density)

EXAMPLE
     function target_alloc0()
	   local chain_call = function()
		 target_alloc("nonauth", function(source, status)
		       print(source, status.kind);
		       if (status.kind == "connected") then
			     chain_call();
		       end
		 end);
	   end
     end

MISUSE
     function target_alloc0()
	   local a = fill_surface(32, 32, 255, 0, 0, 0);
	   target_alloc(a, function(source, status)
	   end);
     end

MISUSE
     function target_alloc1()
	   vid = net_listen();
	   target_alloc(vid, target_alloc);
     end

SEE ALSO:
     define_recordtarget(3) accept_target(3)

targetcontrol			   August 2026			 target_alloc(3)

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