Module Object

A module object is a nonrunnable object that is the output of an ILE compiler. A module object is represented to the system by the symbol *MODULE. A module object is the basic building block for creating runnable ILE objects. This is a significant difference between ILE and OPM. The output of an OPM compiler is a runnable program.

A module object can consist of one or more procedures and data item specifications. It is possible to directly access the procedures or data items in one module from another ILE object. See the ILE HLL programmer’s guides for details on coding the procedures and data items that can be directly accessed by other ILE objects.

ILE RPG, ILE COBOL, ILE C, and ILE C++ all have the following common concepts:
  • Exports

    An export is the name of a procedure or data item, coded in a module object, that is available for use by other ILE objects. The export is identified by its name and its associated type, either procedure or data.

    An export can also be called a definition.

  • Imports

    An import is the use of or reference to the name of a procedure or data item not defined in the current module object. The import is identified by its name and its associated type, either procedure or data.

    An import can also be called a reference.

A module object is the basic building block of an ILE runnable object. Therefore, when a module object is created, the following may also be generated:
  • Debug data

    Debug data is the data necessary for debugging a running ILE object. This data is optional.

  • Program entry procedure (PEP)

    A program entry procedure is the compiler-generated code that is the entry point for an ILE program on a dynamic program call. It is similar to the code provided for the entry point in an OPM program.

  • User entry procedure (UEP)

    A user entry procedure, written by a programmer, is the target of the dynamic program call. It is the procedure that gets control from the PEP. The main() function of a C program becomes the UEP of that program in ILE.

Figure 1 shows a conceptual view of a module object. In this example, module object M1 exports two procedures (Draw_Line and Draw_Arc) and a data item (rtn_code). Module object M1 imports a procedure called Draw_Plot. This particular module object has a PEP, a corresponding UEP (the procedure Draw_Arc), and debug data.

Figure 1. Conceptual View of a Module
Conceptual View of a Module
Characteristics of a *MODULE object:
  • A *MODULE object is the output from an ILE compiler.
  • It is the basic building block for ILE runnable objects.
  • It is not a runnable object.
  • It may have a PEP defined.
  • If a PEP is defined, a UEP is also defined.
  • It can export procedure and data item names.
  • It can import procedure and data item names.
  • It can have debug data defined.