List of Tables

• . Predefined ordinal types
• . Predefined integer types
• . Boolean types
• . Supported Real types
• . AnsiString memory structure
• . PChar pointer arithmetic
• . Set Manipulation operators
• . Precedence of operators
• . Binary arithmetic operators
• . Unary arithmetic operators
• . Logical operators
• . Boolean operators
• . Set operators
• . Relational operators
• . Allowed C constructs in Free Pascal
• . Unsupported modifiers

About this guide

This document describes all constants, types, variables, functions and procedures as they are declared in the system unit. Furthermore, it describes all pascal constructs supported by Free Pascal, and lists all supported data types. It does not, however, give a detailed explanation of the pascal language. The aim is to list which Pascal constructs are supported, and to show where the Free Pascal implementation differs from the Turbo Pascal implementation.

Notations

Throughout this document, we will refer to functions, types and variables with typewriter font. Functions and procedures have their own subsections, and for each function or procedure we have the following topics:

Declaration

The exact declaration of the function.

Description

What does the procedure exactly do ?

Errors

What errors can occur.

See Also

Cross references to other related functions/commands.

The cross-references come in two flavours:

• References to other functions in this manual. In the printed copy, a number will appear after this reference. It refers to the page where this function is explained. In the on-line help pages, this is a hyperlink, on which you can click to jump to the declaration.
• References to Unix manual pages. (For linux related things only) they are printed in typewriter font, and the number after it is the Unix manual section.

Syntax diagrams

All elements of the pascal language are explained in syntax diagrams. Syntax diagrams are like flow charts. Reading a syntax diagram means that you must get from the left side to the right side, following the arrows. When you are at the right of a syntax diagram, and it ends with a single arrow, this means the syntax diagram is continued on the next line. If the line ends on 2 arrows pointing to each other, then the diagram is ended.

Syntactical elements are written like this

Keywords you must type exactly as in the diagram:

When you can repeat something there is an arrow around it:

When there are different possibilities, they are listed in columns:

Note, that one of the possibilities can be empty:

This means that both the first or second possibility are optional. Of course, all these elements can be combined and nested.