RPG TnT

101 Dynamite Tips 'n Techniques with RPG IV

Bob Cozzi

• Publisher: MC Press
• Year: 2012
• eBook ISBN: 9781583476796
• Edition: 0
• Topic: Computer Science
• Subtopic: Programming Languages
• Index: Computer Science

Providing solutions to dozens of technical dilemmas, this guide features 101 tips for evaluating and circumventing RPG IV's shortcomings to help end users create extensions and program features that are not available through standard RPG IV—the primary programming language used for business application development on IBM's midrange computer systems. Using nearly 20 years of AS/400, iSeries, and System i experience, the author's insights into RPG IV extensions and System i MI instructions allow even the most inexperienced programmer to implement wrappers using code directly from the book.

Table of contents

• Title Page
• Copyright Page
• Table of Contents
• Dedication
• Acknowledgments
• Conventions Used in this Book
• 1 - Prototype Everything
• 2 - Prototyping a Call to a Program
• 3 - An Alternative to QCMDEXC
• 4 - Subprocedure-style Entry Parameter List for Programs
• 5 - Add NOMAIN to the Header Specification of Secondary Modules
• 6 - Monitoring C Function Runtime Errors
• 7 - Use PSDS to Retrieve Job Information
• 8 - Use QUALIFIED Data Structures
• 9 - Copy Subfields Between Qualified Data Structures
• 10 - Nested Data Structures
• 11 - *ALL and *ALLX ‘xx’—The Repeating Constants
• 12 - Embed Compiler Parameters into Source Members
• 13 - Avoid “Surprise Initialize”
• 14 - Qualified Externally Described Files (1)
• 15 - Qualified Externally Described Files (2)
• 16 - Calculate the End-of-Month Date
• 17 - Using Free-Format Comments in Fixed-Format Code
• 18 - Get Day-of-Week Name
• 19 - Run CL Commands from an FTP Client
• 20 - Put Your Program to Sleep
• 21 - Use VARYING to Improve Performance
• 22 - Converting Numeric to Character with %CHAR
• 23 - Converting Character to Numeric
• 24 - Easier Text Concatenation
• 25 - Create an Auto-Extend User Space
• 26 - Declare Data Structures as Arrays
• 27 - Initialize Fields to Job Date, System Date, or User Profile
• 28 - Use C Runtime Functions in RPG
• 29 - Compare and Ignore Case
• 30 - Free Online Prototypes for APIs, C Functions, MI Instructions
• 31 - Checking for Valid Dates with the TEST OpCode
• 32 - Using the Secret ‘X’ Edit Code to Convert Numeric to Character
• 33 - %ADDR—Address of a Variable
• 34 - Understanding API Documentation—Bin(4) Parameters
• 35 - Understanding API Documentation—Pointer Parameters
• 36 - Better Performance when Accessing User Space Data
• 37
• 38 - Sending a Program Message in RPG
• 39 - Retrieve the Function Key Used on a Display File
• 40 - Copying More than 64k of Data
• 41 - Use %XFOOT with %LEN
• 42 - Use %SUBARR to Subscript Arrays
• 43 - Use EXTFILE to Avoid Needless Overrides
• 44 - Subprocedure Parameters Rule 1—Default Behavior
• 45 - Subprocedure Parameters Rule 2—CONST Parameters
• 46 - Subprocedure Parameters Rule 3—VARYING
• 47 - Subprocedure Parameters Rule 4—Optional Parameters
• 48 - Subprocedure Parameters Rule 5—Skipping Parameters
• 49 - Data Structure Templates
• 50 - Boolean Assignment
• 51 - Creating Even-Length Packed Fields
• 52 - Sorting Arrays with SubArrays
• 53 - Convert between Lower- and Uppercase Letters
• 54 - Overlapping Data Structures
• 55 - Dynamic Arrays—Dynamically Allocated Array Elements
• 56 - Converting Date Formats with the QWCCVDT API
• 57 - Converting Date Formats with the CEExxxx APIs
• 58 - Calculated Day of Week—Zeller’s Congruence
• 59 - Calculated Day of Week—API Method
• 60 - LIKE Keyword Misbehavior—Zoned to Packed
• 61 - Default Data-type: Not So Consistent
• 62 - Debugging Variables that Have Debugger Command Names
• 63 - Viewing Field Contents in Hex in Debug
• 64 - Display the First Few Bytes During Debug
• 65 - Display Contents of Local Variables with %LOCALVAR
• 66 - Convert Character to Numeric—Using MI
• 67 - Converting To and From Hexadecimal
• 68 - Using Decimal Fields as Real-Date Values
• 69 - Check Object Existence
• 70 - Supporting Qualified Object Syntax
• 71 - Explained: Bytes Provided, Bytes Available, and Bytes Returned
• 72 - Converting To or From ASCII and Other Character Sets
• 73 - Register an Exit Routine for a Program or Service Program
• 74 - Specifying IFS File Names Correctly
• 75 - Checking if IFS Files Exist
• 76 - RC4 Encryption Using Encryption APIs
• 77 - Writing Text to the Joblog
• 78 - Reading Save Files with RPG IV
• 79 - Encrypting Save Files in RPG IV
• 80 - Global and Local Variables
• 81 - Create Source Members Used to Create Service Programs
• 82 - Binder Source for a Service Program
• 83 - Creating Binder Language the Easy Way
• 84 - Linking to a Service Program from an RPG IV Program
• 85 - Swap Bytes—Big Endian to Little Endian in RPG IV
• 86 - Dumping the Call Stack with Qp∅zDumpStack
• 87 - Using Subprocedure Return Values
• 88 - How Does the %EDITC (Edit Code) Built-in Function Work?
• 89 - Solid Parameter Testing
• 90 - Create ASCII Text Files on the IFS
• 91 - High-level Math in RPG IV
• 92 - Program Described Print File with Dynamic Spacing
• 93 - Aligning or Centering Text in a Character Field
• 94 - Debug a Batch Job
• 95 - Find and Replace with Regular Expressions
• 96 - Use DLTOVR when Using OVRDBF OVRSCOPE(*JOB)
• 97 - Use a FOR Loop to Allow Multiple Exit Points
• 98 - Source-level Debugger for Legacy RPG III
• 99 - Set and Get Environment Variables from within RPG IV
• 100 - Simple Scan with Ignore Upper/Lowercase
• 101 - Set the CLASSPATH for Java within RPG IV
• Epilogue
• Appendix - Source Member RPGTnT in QCPYSRC