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link (pseudo-property) - Connection link pseudo-property


module connection;
object example {
  link "map1:local1 direction1 remote1;
  link "map2:local2 direction2 remote2;
  link "mapN:localN directionN remoteN;


The link pseudo-property allow one or more variables to be mapped to and from a remote system during various events in GridLAB-D.

The map may be one of the following:

  • allow : Specifies that a mapping forbidden under STANDARD security should be allowed.
  • deny : Specifies that a mapping allowed under STANDARD security should be forbidden.
  • init : Map during initialization sequence
  • precommit : Map during precommit sequence
  • presync : Map during presync sequence
  • sync : Map during sync sequence
  • postsync : Map during postsync sequence
  • commit : Map during commit sequence
  • plc : Map during PLC sequence
  • finalize : Map during finalize sequence
  • term : Map during termination sequence
  • prenotify : Map before a change to any connection property
  • postnotify : Map after a change to any connection property
  • file : Map using the specifications provided in the specified link file file

The local variable is specified in the form If the form is not found, the list of global variables is searched for a match. The name and the property may be specified using simple pattern matching as prefix*, in which case all names or properties that have the same prefix will be linked.

The direction may be specified as one of the following

  • <- : Copy to local from remote
  • -> : Copy to remote from local
  • <-> : Copy both ways

The remote variable is specified as a string of arbitrary structure terminated by a semicolon or white space. The following special characters will be substituted if encountered

  • \# : GridLAB-D object number
  • \@ : GridLAB-D object name
  • \$ : GridLAB-D object class
  • \\ : A single backslash
  • \! : Lookup local in the link file index

Link file

The link map file is used to provide a connection map with a list of link directives and mapping it should use. The link map contains a section for each map, e.g.,

  local1 direction1 remote1;
  local2 direction2 remote2;
  localN directionN remoteN; 
  localN+1 directionN+1 remoteN+1;
  localN+2 directionN+2 remoteN+2;
  localM directionM remoteM;

In addition the map can contain an index section to translate local names to remote names using the \! special character in the remote name, e.g.,

  local1 remote1
  local2 remote2
  localN remoteN


The following example creates a native connection and maps

module connection;
class test {
  double x;
  double y;  
object test {
  name my;
  x 1.23;
  y 3.45;
object native {
	mode SERVER;
	transport TCP;
	link "precommit:my.x->var1";
	link "commit:my.y<-var2";


The connection module is proposed for Hatwai (Version 3.1). Its development is tracked under Ticket 797.

See also