ExternalObject object

You specify the name of the library in the constructor. The constructor searches for the named library using the paths defined in the static property ExternalObject.searchFolders.

If you are having difficulty loading your library as an ExternalObject, set the property ExternalObject.log to true, then call ExternalObject.search('lib:myLibrary'). This function performs the search, and the log reports the paths that have been searched to the ExtendScript Toolkit Console.

Before loading the library, the current folder is temporarily switched to the location of the found executable file.

  • In Mac OS, the current directory is set to the bundle or framework folder for the library.

  • In Windows and UNIX, the current directory is set to the folder that contains the library.

ExternalObject constructor

obj = new ExternalObject ("lib:" + filespec, arg1, ...argn);


The specifier “lib:” is case sensitive, and serves as the marker for dynamic libraries. Concatenate this to the base name of the shared library, with or without an extension. ExtendScript appends a file extension if necessary, according to the operating system:

  • .dll in Windows

  • .bundle or .framework in Mac OS (only Mach-O bundles are supported)

  • .so in UNIX (except for HP/UX, where the extension is .sl )

The name of the library is case sensitive in UNIX.


Optional. Any number of arguments to pass to the library’s initialization routine.

For example:

var mylib = new ExternalObject( "lib:myLibrary" );

ExternalObject class properties

The ExternalObject class provides these static properties:



Set to true to write status information to standard output (the JavaScript Console in the ExtendScript Toolkit). Set to false to turn logging off. Default is false.



A set of alternate paths in which to search for the shared library files, a single string with multiple path specifications delimited by semicolons (;). Paths can be absolute or relative to the Folder.startup location. Default value is:

  • In Windows, "Plugins;Plug-Ins;."

  • In Mac OS, "Plugins;Plug-Ins;Frameworks;.;../../../Plugins; ../../../Plug-ins;../../../Frameworks;../../..;"

  • In UNIX, "Plugins;Plug-Ins;plugins;."



The version of the library, as returned by ESGetVersion().

ExternalObject class function

The ExternalObject class provides this static function to help debug problems with loading libraries as external objects:

ExternalObject instance function


ExternalObject_obj.terminate ()

Explicitly shuts down the ExternalObject dynamic library wrapped by this instance.

It can be helpful to force a shutdown of the external library if termination of external libraries during the shutdown of the hosting application does not occur in the correct order.

Returns undefined.