Integration Guide

Table Of Contents

Customizing the PSS System Software

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WaveWorks PSS, Integration Guide, 1.10 Page 105

Writing custom COM Objects requires a solid programming background, preferably using Visual

C++ and the ATL wizard.

9.4 User Exit DLL

A DLL, PssUserExits.dll, is provided which allows integration teams to customize the software

for a given installation. This mechanism is equivalent to the User Exits used in the PSA

software. The DLL contains functions that have been built into the code, but that, in most cases,

contain stubs that only log a debug level message to identify that the function was called. The

integrator is then allowed to add appropriate code to the functions and rebuild the dll.

The C++ language header file PssUserExits.h documents the intended purpose of each function,

the detail of the function interfaces, and the return status codes expected by the base PSS

software. It also documents how the various return code values will affect the operation of the

base PSS software when the function returns.

Each User Exit function is implemented in a separate C++ source file named

<UserExitName>.cpp. This C++ source file contains the stub code for the function.

9.4.1 Common Information

All methods should return one of three return status codes as described below. The return code

is the last argument in the call list to the User Exit function.

The following description of standard arguments which are passed to all user exits applies to

C++ modules only. User Exits called from "C" only code will not include the arguments which

are C++ objects.

A C++ source module with the same name as the function name is supplied with a stub

implementation routine for the User Exit. The stub routine "includes" the PssUserExits.h file to

retrieve the function definition. All stubs return status UE_CONTINUE to the calling routine.

Many of the stub routines log a debug level message to the PSS System Log with the values of

all the input arguments. This stub code can be reviewed to see how to use the CPssMsgLog

object to write messages to the PSS System Log. See also the following section "Using the

CPssMsgLog Class."

If a "Preprocess" User Exit needs to pass information to a "Postprocess" User Exit for the same

PSS function (PreProcessRecord -> PostProcessRecord), it can be maintained in static storage in

the dll. All other information exchange between user exits cannot safely rely on executing

within the same instance of the dll. In those cases the User Exits must use other mechanisms for

sharing information between user exit functions.