BORLAND
Turbo Pascal®
Reference Guide
Version 5.0
Copyrightc 1983,1989 All rights reserved Borland International 1800 Green Hills Road P.O. Box 660001 Scotts Valley, CA 9~1
R3
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Copyrighto 1989 Borland International.
Printed in the U.S.A.
109876543
Table of Contents
Introduction 1
What's On Your Disks 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Installing Turbo Pascal On Your System 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 About This Manual 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • 0 • 0 0 4 Typography 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 How to Contact Borland 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 5 Part 1 Programmer's Reference
Chapter 1 Tokens and Constants 9
Special Symbols and Reserved Words 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 Iden tifiers 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • 0 0 0 0 11
!.abels 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • • • • • • • 0 0 0 0 0 0 0 0 0 0 12 Numbers 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13 Character Strings 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 14 Constant Declarations 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 15 Comments 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 16 Program Lines 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 16 Chapter 2 Blocks, Locality, and Scope 17 Syntax 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . 0 17 Rules of Scope 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 19 Scope of Interface and Standard Identifiers 0 0 0 0 0 0 0 • • • 0 • 0 • • • • 0 0 0 0 0 0 0 0 19
Chapter 3 Types 21
Simple Types 0 0 0 0 0 0 • 0 • • 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 • 0 0 0 • 0 • 0 • 0 0 0 0 0 0 0 . 0 0 • • 0 22 Ordinal Types . 0 0 0 0 0 • • • 0 • 0 • 0 0 0 0 0 • 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 • 0 • • 22 Integer Types o. 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • • • 0 0 0 0 0 0 0 • • 0 23 Boolean Type 0 0 0 0 0 0 • 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 • • 0 0 0 • 0 0 0 0 0 0 0 0 o . 24 Char Type 0 0 0 • 0 0 0 • 0 0 0 0 0 0 • • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 24 Enumerated Types 0 0 0 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 • • • 0 0 0 0 0 . 0 • • • • • 0 0 . 0 0 0 0 • • 24 Subrange Types 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • 0 0 0 0 0 0 0 0 0 • 0 • • 0 0 0 0 0 0 0 0 • • 25 Real Types 0 0 0 0 0 0 0 0 0 0 • 0 • 0 • • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 • • 0 0 0 0 0 0 0 0 • 0 0 0 • 0 26 Software Floating Point 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 • • 0 0 0 0 0 26 8087 Floating Point 0 0 0 0 • 0 • 0 0 0 0 0 0 0 0 • 0 • 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 • 0 0 • • 0 27 String Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • • 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 27 Structured. Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 28 Array Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 28 Record Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 29 Set Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 31 File Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 31
Pointer Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 32 Procedural Types 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 33 Identical and Compatible Types 0 . 0 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • 0 0 0 0 0 0 33 Type Identity 0 " 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 • 0 0 • 0 • 0 0 0 • 0 0 33 Type Compatibility 0 0 • 0 0 0 0 • 0 0 • 0 0 • 0 • 0 0 0 0 0 • • 0 0 0 0 • 0 0 0 • • 0 0 0 0 0 0 0 0 0 • • 34 Assignment Compatibility ... 0 . . 0 0 0 0 0 . . 0 . . 0 • • • • 0 . . . 0 0 • • 0 • • 0 34 The Type Declaration Part .. 0 0 • 0 0 0 0 • 0 • 0 0 0 0 0 • 0 0 • 0 0 0 0 0 0 • 0 • 0 0 0 0 • • • 0 • 0 35
Chapter 4 Variables 37
Variable Declarations 0 0 0 0 • • 0 0 0 • • 0 0 0 0 0 0 . 0 0 0 • • • • 0 0 0 • • 0 0 0 0 0 0 0 0 0 0 0 • • 0 37 The Data Segment 0 0 0 0 0 0 0 0 0 • 0 • 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 • 0 0 0 0 0 0 0 0 • 0 0 38 The Stack Segment 0 0 0 • • • 0 0 0 0 • 0 • 0 0 0 0 0 0 0 0 0 • 0 • 0 0 • 0 0 0 • 0 0 0 0 • 0 0 0 0 0 • • 38 Absolute Variables 0 0 0 0 0 • • • • 0 . 0 0 . 0 0 0 0 0 0 0 0 0 . 0 . 0 0 0 0 0 0 . 0 0 0 0 0 0 . 0 0 0 0 39 Variable References .. 0 • 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • • 0 0 0 0 0 0 0 0 0 0 0 • • 0 0 39 Qu.alifiers 0 0 0 0 0 0 0 0 0 • 0 0 • 0 • 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 • • • 0 0 0 0 • 0 0 0 • 0 40 Arrays, Strings, and Indexes ... 0 0 0 0 • 0 0 0 0 0 • • 0 0 0 0 • 0 • 0 0 0 0 0 0 0 0 0 • 0 • • 0 41 Records and Field Designators. 0 " 0 0 " 0 . 0 0 . 0 . . 0 0 0 0 . . . 0 . . . . 0 0 0 • • 0 41 Pointers and Dynamic Variables . 0 0 0 0 0 0 0 0 0 0 • 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 42 Variable Typecasts 0 0 0 0 0 0 0 . 0 0 0 • • 0 0 . 0 . 0 0 0 0 0 0 . 0 0 . 0 ' . 0 • • • 0 0 0 0 0 0 0 • • 0 • • 42
Chapter 5 Typed Constants 45
Simple-Type Constants 0 • • 0 • 0 0 0 0 0 • 0 • 0 0 0 0 • 0 0 0 • 0 • 0 0 0 0 0 0 0 • 0 0 0 0 0 • 0 • 0 0 46 String-Type Constants 0 0 • • • 0 . 0 0 • • • 0 • 0 0 0 0 • • • • 0 • 0 0 . 0 0 0 0 0 0 0 0 0 0 0 . 0 • • • 46 Structured-Type Constants o. 0 • • • • • • 0 . 0 . 0 0 0 0 0 0 0 0 0 0 . 0 0 0 0 0 . 0 0 0 0 0 0 . 0 0 46 Array-Type Constants 0 • • 0 0 0 0 0 • 0 0 0 0 0 0 • 0 0 0 0 0 0 • 0 • 0 0 0 0 0 • 0 0 0 0 0 0 • • • 0 47 Record-Type Constants .. 0 0 0 0 0 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . 0 0 0 . 0 0 • • 0 0 0 0 0 . 0 . 0 48 Set-Type Constants .. 0 0 • • 0 0 0 • • • 0 0 0 0 • 0 0 0 0 0 0 0 • 0 0 • • 0 0 0 • 0 • 0 0 0 • 0 • 0 0 "0 48 Pointer-Type Constants 0 0 0 • • 0 0 • • 0 0 • 0 • 0 0 0 0 0 0 • • 0 0 0 0 0 0 0 • 0 0 0 0 0 0 • 0 0 • 0 0 49
Chapter 6 Expressions 51
Expression Syntax 0 • • • 0 0 • • • 0 0 0 0 0 • 0 • • 0 • 0 0 0 0 • • 0 0 0 0 0 • 0 0 • • 0 • 0 0 0 0 • 0 • • • 52 Operators .. 0 0 0 0 0 0 0 • • • 0 0 • • • 0 • • • 0 0 • 0 • 0 • 0 0 • • • 0 • • 0 0 0 • 0 0 0 • • 0 0 0 0 0 • • o . 54 Arithmetic Operators 0 0 0 0 0 0 0 0 • • • 0 0 0 0 • 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . 0 0 54 Logical Opera tors ... 0 • • • • • • • • • • • • • • • • • • • • • • • • • • 0 0 • • • • • • • 56 B<>olean Operators 0 • • 0 • • 0 0 0 0 0 0 0 . 0 0 0 . 0 • • 0 • 0 0 0 0 0 • • 0 . 0 0 0 . 0 0 . 0 0 0 0 . 0 56 String Operator . 0 • • • 0 • • 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 • 0 0 0 0 0 • 0 0 • • 0 • 0 0 0 0 • 0 • 0 0 57 Set Operators 0 0 0 0 0 • 0 • 0 0 • 0 0 0 0 0 0 0 0 0 • • 0 • 0 0 0 0 • • • • 0 0 0 0 0 0 • • 0 0 • 0 0 0 • • • 58 Relational Operators 0 0 0 • • 0 0 0 0 0 0 0 0 0 0 0 . 0 0 0 0 0 • • 0 0 0 0 0 0 0 0 0 • 0 0 0 . 0 0 • • • 58 Comparing Simple Types 0 0 0 0 0 • • 0 0 • 0 0 • • 0 0 • 0 0 0 0 0 • • 0 0 • • 0 0 0 0 0 0 • • • 59 Comparing Strings 0 0 • • 0 0 0 0 0 0 • 0 0 0 • 0 • 0 • • • • • • 0 0 • 0 0 0 • • • 0 0 0 • • • • • • 59 Comparing Packed Strings . 0 • • 0 0 0 • 0 • • 0 0 • • 0 • 0 0 • 0 0 0 • • • • 0 0 0 • 0 0 • • 60 Comparing Pointers ... 0 • • • 0 0 • • • 0 • • • • • • 0 0 0 • 0 • 0 0 • • 0 0 0 • • 0 0 • 0 60 Comparing Sets ... 0 • • • • • • 0 • • • • • • 0 • 0 • • • 0 0 • 0 0 0 • • 0 0 0 0 • • 0 0 • 0 0 0 0 0 60 Testing Set Membership .. 0 0 0 0 • • 0 • • 0 0 • • 0 0 • 0 0 0 0 0 • • • 0 0 • 0 0 • 0 0 • 0 0 0 60 The @ Operator 0 0 0 • • • • • • • 0 0 0 • • • • • • • • • 0 0 0 0 • • • • 0 0 0 0 • • • • • 0 0 • • • • • 0 61
@ with a Variable .. 0 0 0 0 0 0 • 0 • 0 0 • • • • 0 0 0 0 0 • • • 0 0 0 0 • • 0 . 0 • 0 0 0 • 0 • • • • 61
@ with a Value Parameter ... 61
@ with a Variable Parameter ... 0 • • • • • • • • • • • • • • • • • • • • • • • • • • 62 @ with a Procedure or Function .... 0 • • • • • • • • • • • • • • • • • • • 0 • • • • • • 62 Function Calls ... 0 • • • • • • • • • • • • • • • • • • • • • 0 • • • • 62 Set Constructors ... 0 • • • • • • • • • • • • • • • • • • • 0 • • 0 0 • • 63 Value Typecasts ... 0 • • • • • • • • • • • 0 • • • • • • • • • • • • • • • • • • • 0 • 0 • • • • 64 Chapter 7 Statements 65 Simple Statements ... 0 • • • • • • • 0 • • • • 0 • • 0 • • • 0 • • • 0 • • • • • • • 0 • • 0 • • • • 65 Assignment Statements ... 0 • • • • • • • • • • • • • • • • • • • • • 0 • • • • 66 Proced.ure Statements ... 0 • • • • 66 Goto Statements ... 0 • • • • 67 Structured Statements ... 0 • • • • • • • • • • • • • • • • • • • • • • • • • • 67 Compound Statements ... 0 • • • • • • • • • • • • • • • • • 0 • • • • • • • • • • 0 • • • • 67 Conditional Statements ... 0 • • • • • • • • • • • • • • • • • • • • • 0 • • • • 68 If Statements ... 0 • • • • 68 Case Statements ... 0 • • • • • • • • • • • • • • 0 • • • • 69 Repetitive Statements ... 0 • • • • • • • • • • • 0 • • • • 70 Repeat Statements ... 0 • • • • 70 While Statements ... 0 • • • 0 ~ • • • • • • • • • 0 • • • • 71 For Statements ... 0 • • • • 72 With Statements ... 74
Chapter 8 Procedures and Functions 77 Procedure Declarations ... ' .. 0 • • • • • • • • 77 Forward Declarations ... 78
External Declarations ... 79
Inline Declarations ... 80
Function Declarations . . . .. 80
Parameters ... . Value Parameters ... . Variable Parameters ... . Untyped Variable Parameters ... . Procedural Types ... . Procedural Type Declarations ... 0 • • • • • • • • •
Procedural Variables ... o • • • • • • • • • • • • • • • • • • • • • • • • • • Procedural Type Parameters ... 0 • • • • • • • • • • • • • • • • • • •
Procedural Types in Expressions ... . Chapter 9 Programs and Units Program Syntax ... 0 0 • • • • • • • • • 0 • 0 • • • • • • • • • • • • • • • • • • • • • • • • • • • The Program Heading o. 0 • • • • • • • • • • • • • • • • • • • • • 0 • • • • • • • • • • • • • • • • The Uses Clause ... , ... 0 • • • • • • •
Unit Syntax ... . The Unit Heading ... 0 • • • • • • • • • • • • • 0 • • • • • • • • • • • • • • •
The Interface Part ... 0 • • • • • • • • • • • • • • • • 0 • • • • • • • • • • • • • • • •
82 82 83 83 84 84 85 87 89 93 93 93 93
94
95 95
The Implementation Part .. . . .. 95
The Initialization Part ... 96
Indirect Unit References . . . .. 96
Circular Unit References ... 97
Sharing Other Declarations ... 99
Chapter 10 Input and Output 101 An Introduction to I/O ... 101
Standard Procedures and Functions for All Files . . . .. 102
Procedures ... 102
Functions ... 103
Standard Procedures and Functions for Text Files ... 103
Procedures ... 104
Functions ... 104
Standard Procedures and Functions for Untyped Files. . . .. 105
The FileMode Variable. . . .. . .. . . .. . . .. . .. . .. . . ... 105
Devices in Turbo Pascal ... 106
OOS Devices ... 106
The CON Device ... 107
The LPT1, LPT2, and LPT3 Devices ... 107
The COM1 and COM2 Devices . . . .. 107
The NUL Device ... 107
Text File Devices ... 108
Chapter 11 Standard Procedures and Functions 109 Flow Control Procedures ... 109
Dynamic Allocation Procedures and Functions ... . . . .. 109
Procedures ... ' ... 110
Functions ... 110
Transfer Functions ... 110
Arithmetic Functions ... 110
Ordinal Procedures and Functions. . . .. 111
Procedures ... 111
Functions ... '. . . . .. 111
String Procedures and Functions ... 112
Procedures ... 112
Functions ... 112
Pointer and Address Functions. . . .. 112
Miscellaneous Procedures and Functions ... 112
Procedures ... 112
Functions ... 113
Chapter 12 Standard Units 115 Standard Unit Dependencies. . . .. 116
The System Unit ... 116
The Printer Unit ... 119
