< Pascal Programming

Appendix

Noteworthy types

type definition size (in bytes) availability
AnsiChar one ANSI-standard textual character 1
AnsiString an array of ANSI-standard characters of indefinite length with an optional size constraint 1 * number of characters
Boolean true or false 1 standard
Byte whole number ranging from 0 to 255 1
Cardinal synonym depending on processor type (16 bit=Word, 32 bit=LongWord, 64 bit=QWord) varies (2, 4, 8)
Char one textual character (likely ASCII) 1 standard
Comp a floating point number ranging 19-20 digits that is effectively a 64-bit integer 8
Currency a floating point number ranging 19-20 digits that is a fixed point data type 8
Double a floating point number ranging 15-16 digits 8
DWord whole number ranging from 0 to 4,294,967,295 4
Extended a floating point number ranging 19-20 digits 10
Int64 whole number ranging from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 8
Integer synonym depending on processor type (16 bit=SmallInt, 32 bit=LongInt, 64 bit=Int64) varies (2, 4, 8) standard
LongInt whole number ranging from -2,147,483,640 to 2,147,483,647 4
LongWord whole number ranging from 0 to 4,294,967,295 4
Pointer an untyped pointer holding an address 32 bit=4, 64 bit=8 standard
PtrUInt a pointer type implicitly convertable to an unsigned integer 32 bit=4, 64 bit=8
QWord whole number ranging from 0 to 18,446,744,073,709,551,615 8 Free Pascal
Real a floating point number whose range is platform dependent 4 or 8 standard
ShortInt whole number ranging from -128 to 127 1
ShortString an array of textual characters of up to 255 elements (likely ASCII) with an optional size constraint 1 * number of characters (max 255) standard
Single a floating point number ranging 7-8 digits 4
SmallInt whole number ranging from -32,768 to 32,767 4
String synonym for ShortString (or AnsiString with the $H preprocessor directive turned on) 1 * number of characters (max 255) standard
UInt64 whole number ranging from 0 to 18,446,744,073,709,551,615 8 Free Pascal, Delphi 8 or later
WideChar one UTF-8 textual character 2
WideString an array of UTF-8 characters of indefinite length with an optional size constraint 2 * number of characters
Word whole number ranging from 0 to 65,535 2

Noteworthy preprocessor directives

directive description value(s) example availability
$COPERATORS allows use of C-style operators OFF or ON 
{$COPERATORS ON}
i += 5;
i -= 5;
i *= 5;
i /= 5;
Free Pascal
$DEFINE defines a symbol for the preprocessor (if '$macro on', can have a value assigned) symbol name (:= value if '$macro on') 
{$DEFINE Foo}
{$DEFINE Bar := 5}
standard
$H implies whether the String type is a ShortString or AnsiString - or + Delphi, Free Pascal
$I inserts a file's contents into the current source code filename 
{$I hello.txt}
standard
$IF begins a preprocessor conditional statement compile-time boolean expression 
{$IF DEFINED(DELPHI) OR DECLARED(Foo)}
standard
$IFDEF begins a preprocessor conditional statement depending if a preprocessor symbol is defined preprocessor symbol 
{$IFDEF MSWINDOWS}
standard
$IFNDEF begins a preprocessor conditional statement depending if a preprocessor symbol is not defined preprocessor symbol 
{$IFNDEF UNIX}
standard
$IFOPT begins a preprocessor conditional statement depending on the status of a preprocessor switch compiler option 
{$IFOPT D+}
standard
$INCLUDE inserts a file's contents into the current source code filename 
{$INCLUDE hello.txt}
standard
$INLINE allows inline functions and procedures OFF or ON 
unit Foo;
{$INLINE ON}
interface
  function Give5: integer; inline;
implementation
  function Give5: integer;
  begin
    Give5 := 5;
  end;
end.
Free Pascal
$MACRO allows defined symbols to hold values OFF or ON 
{$MACRO ON}
{$DEFINE Foo := 7}
Free Pascal
$MODE sets the Pascal dialect DELPHI, FPC, MACPAS, OBJFPC, TP Free Pascal
$R embeds a resource file into the code a file name 
{$R *.dfm}
Delphi, Free Pascal
$STATIC allows use of the 'static' keyword OFF or ON 
unit Foo;
{$STATIC ON}
{$MODE OBJFPC}
interface
  type
    Bar = class
      function Baz: string; static;
    end;
implementation
  function Bar.Baz: string;
  begin
    Result := 'This function is not part of a Bar instance.';
  end;
end.
Free Pascal
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