IBM AS/400 Manuel D’Utilisation

RPG Programming in ILE

CEEDOD – Decompose Operational Descriptor

Note: You cannot use these or any other ILE bindable APIs from within a program

created with DFTACTGRP(*YES). This is because bound calls are not
allowed in this type of program.

For more information on these ILE bindable APIs, see Chapter 9, “Running a
Program” on page 103 and also the

System API Reference.

Multithreaded Applications

The AS/400 now supports multithreading. ILE RPG does not directly support initi-

ating or managing program threads. However, ILE RPG procedures can run as

threads in multithreaded environments. If you want to call an ILE RPG procedure in

a multithreaded application, you must ensure that the ILE RPG procedure is

threadsafe. You must also ensure that any system functions that your procedure

accesses are also threadsafe.

The THREAD(*SEREALIZE) control specification keyword can be specified to help

you achieve thread safety for an ILE RPG module. Specifying

THREAD(*SERIALIZE) will protect most of your variables and all your internal

control structures from being accessed improperly by multiple threads. The thread

safe module will be locked when a procedure in the module is entered and

unlocked when when no procedure in the module is still running. This serialized

access, ensures that only one thread is active in any one module, within an acti-

vation group, at any one time. However, it is still up to the programmer to handle

thread safety for storage that is shared across modules. This is done by adding

logic in the application to synchronize access to the storage.

For more information, see “Multithreading Considerations” on page 157.

Chapter 2. RPG Programming in ILE