About Loading ObjectARX Applications

An ObjectARX application must be loaded before you can use any of its defined commands or functions.

You can load an ObjectARX application using one of the following approaches:

• Load option of the ARX or APPLOAD command and manually specify which ObjectARX application to load
• Startup Suite of the APPLOAD command to automatically load an ObjectARX file
• arxload AutoLISP function and specify which ObjectARX application to load

Note: Starting with AutoCAD 2014-based products, custom applications must work under secure mode; when the SECURELOAD system variable is set to 1 or 2. When operating under secure mode, the program is restricted to loading and executing files that contain code from trusted locations; trusted locations are specified by the TRUSTEDPATHS system variable.

Automatically Load ObjectARX Applications

Note: Some ObjectARX applications use large amounts of system memory. If you are finished using an application and want to remove it from memory, use the Unload option of the ARX or APPLOAD command.

Some ObjectARX samples contain an acad.rx file, which lists ObjectARX application files that are loaded automatically when you start AutoCAD.

You can create or edit this file with a text editor or word processor that produces files in ASCII text format, adding to or deleting from its contents to make the appropriate ObjectARX applications available for use. As an alternative, the APPLOAD command provides a Startup Suite option that loads the specified applications without the need to edit any files.

Because AutoCAD and AutoCAD-based products search for the acad.rx file in the order specified by the library path, you can have a different acad.rx file in each drawing directory. This makes specific ObjectARX applications available for certain types of drawings. For example, you might keep 3D drawings in a directory called AcadJobs/3d_dwgs. If that directory is set up as the current directory, you could copy the acad.rx file into that directory and modify it in the following manner:

myapp1
otherapp

If you place this new acad.rx file in the AcadJobs/3d_dwgs directory and you start the program with that as the current directory, these new ObjectARX applications are then loaded and are available from the command prompt. Because the original acad.rx file is still in the directory with the AutoCAD program files, the default acad.rx file will be loaded if you start the program from another directory that does not contain an acad.rx file.

You can load ObjectARX applications from an MNL file using the arxload function. This ensures that an ObjectARX application, required for proper operation of a menu, will be loaded when the menu file is loaded.

Load an ObjectARX Application with AutoLISP

The syntax for the arxload function is almost identical to that of the load function used with AutoLISP files. If the arxload function loads the ObjectARX application successfully, it returns the program name. The syntax for the arxload function is as follows:

(arxload filename [onfailure])

The two arguments for the arxload function are filename and onfailure. As with the load function, the filename argument is required and must be the complete path name description of the ObjectARX application file to load. The onfailure argument is optional and typically not used when you load ObjectARX applications from the Command prompt. The following example loads the ObjectARX application myapp.arx.

(arxload "myapp")

As with AutoLISP files, the program searches the library path for the specified file. If you need to load a file that is not in the library path, you must provide the full path name description of the file.

Note: When specifying a directory path, you must use a slash (/) or two backslashes (\\) as the separator, because a single backslash has a special meaning in AutoLISP.

Attempting to load an application that has previously been loaded results in an error. Before using arxload you should use the arx function to check the currently loaded applications.

To unload an application with AutoLISP, use the arxunload function. The following example unloads the myapp application.

(arxunload "myapp")

Using the arxunload function not only removes the ObjectARX application from memory but also removes the command definitions associated with that application.