IBM i Fundamentals

An ordered path through the foundational IBM i concepts every beginner and working developer benefits from knowing.

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Showing 17 of 288 lessons

7Introduction to RPGLELog in to accessWhat RPGLE is, how it's used to build IBM i business applications, and how it connects to what you've learned so far.
33RPGLE Program StructureLog in to accessThe main parts of a simple free-format RPGLE program: control options, declarations, calculations, and program end.
34RPGLE Source Layout and Free Format BasicsLog in to accessThe basic layout rules of free-format RPGLE source: the **free marker, semicolons, comments, and indentation.
35Variables and Data Types in RPGLELog in to accessHow to declare a simple RPGLE variable using dcl-s, and common RPGLE data types like char, packed, int, and ind.
36Constants and Literals in RPGLELog in to accessWhat a literal value is, what an RPGLE constant (dcl-c) is, and why named constants are often better than repeated literals.
37Expressions and Assignment in RPGLELog in to accessHow to read and write RPGLE assignment statements, and common arithmetic and comparison operators used in expressions.
38IF / ELSE in RPGLELog in to accessHow to read and write if / elseif / else blocks in free-format RPGLE using comparison operators.
39SELECT / WHEN / OTHER in RPGLELog in to accessHow to read and write select / when / other blocks in free-format RPGLE, and when they beat a long elseif chain.
40DO Loops and Basic Iteration in RPGLELog in to accessHow to read and write for, dow, and dou loops in free-format RPGLE, and when each one is a natural fit.
41Built-in Functions in RPGLELog in to accessWhat RPGLE built-in functions (BIFs) are, and how to use %TRIM, %LEN, %SUBST, %CHAR, and %DEC.
42Data Structures in RPGLELog in to accessHow to declare an RPGLE data structure with dcl-ds, group related subfields, and why qualified is good practice.
43Arrays in RPGLELog in to accessHow to declare an RPGLE array with dim, access elements by index, and loop through an array.
44Indicators in Modern RPGLELog in to accessWhy numbered indicators (*IN01-*IN99) were historically common, and why modern RPGLE favors named indicator variables.
45Procedures and Subprocedures in RPGLELog in to accessWhy RPGLE programs are broken into subprocedures, and how to write and call a simple one with dcl-proc.
46Parameters and Prototypes in RPGLELog in to accessHow to write a subprocedure that accepts parameters and returns a value using dcl-pi, and what a prototype is for.
47Basic Error Handling in RPGLELog in to accessWhy error handling matters in RPGLE, and how to use monitor / on-error / endmon to catch a runtime error.
48Debugging RPGLE ProgramsLog in to accessBeginner-friendly ways to investigate an RPGLE program: dsply tracing, the ILE source debugger, and job logs.