Preface
Endless PL/I for POSIX Systems is a strict superset of the ANSI X3.74-1981 PL/I General Purpose Subset and provides most of the features of the new ANSI X3.74-1987 PL/I General Purpose Subset and many of the features of the ANSI X3.53-1976 (full) PL/I language standard.
1. Intended Audience
This manual is intended for programmers using PL/I to design or implement applications on Linux, macOS, Tru64 UNIX and other POSIX systems. A prerequisite for attaining optimal benefit from the manual is that its users understand the concepts of programming in PL/I and are familiar with the keywords and topics that will be searched for information.
This manual is not suitable for use as a tutorial document.
2. Associated Documents
The Endless PL/I for POSIX Systems User's Manual provides information on program development with the system-specific command language, the extensive I/O capabilities provided in PL/I, and programming techniques available to PL/I programs executing under the exclusive control of the operating system.
For information on installing PL/I, see the Endless PL/I for POSIX Systems Installation Guide.
3. Conventions
| Conventions | Meaning |
|---|---|
| Return | This symbol represents a single stroke of the RETURN key on the keyboard. |
| Ctrl+X | This symbol represents a control key combination. The letter X can be any keyboard character. To generate a control key combination, hold down the CTRL key while pressing the specified letter. |
| command | System text and code in examples and in text appears in the Courier typeface. Since the UNIX operating system differentiates between lowercase and uppercase characters, literal strings in examples and text must be entered exactly as shown. |
| bold | User input in interactive examples appears in the bold Courier typeface. |
| bold | Bold words in text indicate the first use of a new term. |
| italic | File and variable names appear in italics. |
| ⋮ | Vertical ellipses indicate that irrelevant parts of the program text or program output have been omitted. |
| quotation mark apostrophe | The term quotation mark is used only to refer to the double quotation mark character ("). The term apostrophe is used to refer to the single quotation mark character ('). |
| # | A # symbol is used in some contexts to indicate a single ASCII space character.) |
pl1(1) | Specifies a manual page. For more information, type: man section page |
| This margin icon indicates that the paragraph contains important information to which you should pay close attention. |
| SYNTAX | Syntax (format) diagrams appear in the Helvetica typeface. |
| . . . | Horizontal ellipses indicate that additional parameters, options, or values can optionally be entered. When a comma precedes an ellipsis, it indicates that successive items must be separated by commas. Used in syntax diagrams. |
| [ ] | Square brackets indicate that a syntactic element is optional and you need not specify it. Used in syntax diagrams |
[ LIST ] [ EDIT ] | Brackets surrounding two or more stacked items indicate conflicting options, one of which can optionally be chosen. Used in syntax diagrams |
{ EXTERNAL }
{ INTERNAL } | Braces surrounding two or more stacked items indicate conflicting options, one of which must be chosen. Used in syntax diagrams |
FILE (file-reference) | An uppercase word or phrase indicates a keyword that must be entered as shown; a lowercase word or phrase indicates an item for which a variable value must be supplied. This convention applies to syntax diagrams, not to code examples. |
4. Technical Assumptions
All descriptions of the effects of executing statements and evaluating expressions assume that the initial procedure activation of the program is through an entry point with OPTIONS(MAIN).
It is further assumed that any non-PL/I procedures called by the program follow all PL/I calling conventions and all conventions of the PL/I run-time environment. Except as explicitly noted, descriptions of I/O statements do not cover the effects of system-specific options.
For details on mixed-language programming and system-specific options, see the Endless PL/I for POSIX Systems User's Manual.
5. Terminological Conventions
Information in this manual applies to the use of Endless PL/I for POSIX Systems on Linux, macOS, Tru64 UNIX and other POSIX systems unless otherwise indicated.
The term PL/I refers to Endless PL/I for POSIX Systems.
The terms "full PL/I" and "standard PL/I" refer to the ANSI standard PL/I, X3.53—1976.