CL Programming

Objects

The functions performed by most of the CL commands are applied to objects. Some commands can be used on any type of object and others apply only to a specific type of object.

The system supports various unique types of objects. Some types identify objects common to many data processing systems, such as:

Other object types are less familiar, such as:

Different object types have different operational characteristics. These differences make each object type unique. For example, because a file is an object that contains data, its operational characteristics differ from those of a program, which contains instructions.

Each object has a name. The object name and the object type are used to identify an object. The object name is assigned by the user creating the object. The object type is determined by the command used to create the object. For example, if a program was created and given the name OEUPDT (for order entry update), the program could always be referred to by that name. The system uses the object name (OEUPDT) and object type (program) to locate the object and perform operations on it. Several objects can have the same name, but they must either be different object types or be stored in different libraries.

The system maintains integrity by preventing the misuse of certain functions, depending on the object type. For example, the command CALL causes a program object to run. If you specified CALL and named a file, the command would fail unless there happened to be a program with the same name.


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