The process of getting a program or service program ready to run is known as activation. Activation allocates resources within a job so that one or more programs can run in that space. When a program is called, ILE automatically initiates the activation group specified for the program. If the specified activation group for a program does not exist when the program is called, it is created within the job to hold the program's activation.
In ILE, you can write programs in which ILE C++, OPM, and EPM programs can work together by using dynamic program calls. When using such calls, the calling program specifies the name of the called program. This name is resolved to an address at run time, just before the calling program passes control to the called program.
You can optimize the use of dynamic program calls by using static procedure calls. Because the procedure names are resolved at bind time (that is, when you create the program), static procedure calls are faster than dynamic calls.
In addition, static procedure calls allow operational descriptors. Operational descriptors are used to call bindable APIs or procedures written in other ILE languages.
See Chapter 23, Using ILE C/C++ Call Conventions for information on calls between programs and procedures.
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