Using preinitialization

From a non-Language Environment-conforming driver (such as assembler) you can use Language Environment preinitialization facilities to create and initialize a common runtime environment, execute applications written in a Language Environment-conforming HLL multiple times within the preinitialized environment, and terminate the preinitialized environment. Language Environment provides a preinitialized interface to perform these tasks.

In the preinitialized environment, the first routine to execute can be treated as either the main routine or a subroutine of that execution instance. Language Environment provides support for both of these types of preinitialized routines:

Executing one main routine multiple times
Executing subroutines multiple times

Language Environment preinitialization is commonly used to enhance performance for repeated invocations of an application or for a complex application where there are many repetitive requests and where fast response is required. For instance, if an assembler routine invokes either a number of Language Environment-conforming HLL routines or the same HLL routine a number of times, the creation and termination of that HLL environment multiple times is needlessly inefficient. A more efficient method is to create the HLL environment only once for use by all invocations of the routine.

The interface for preinitialized routines is a loadable routine called CEEPIPI. This routine is loaded as an RMODE(24) / AMODE(ANY) routine and returns in the AMODE of its caller when the request is satisfied.

CEEPIPI handles the requests and provides services for environment initialization, application invocation, and environment termination. All requests for services by CEEPIPI must be made from a non-Language Environment environment. (Preinitialization interface contains a detailed description and information about how to invoke each of these services.) The parameter list for CEEPIPI is an OS standard linkage parameter list. Each request to CEEPIPI is identified by a function code that describes the CEEPIPI service and that is the first parameter in the parameter list. The function code is a fullword integer (for example, 1 = init_main, 2 = call_main).

The preinitialization services offered under Language Environment are listed in Table 1. Preinitialization services do not support PL/I multitasking applications.

An example assembler program in An example program invocation of CEEPIPI illustrates invocation of CEEPIPI for the function codes init_sub, call_sub, and term.