| Description |
The SizeOf function returns the storage size, in bytes, of either a Variable or Type.
It is often useful to know exactly how much space data is taking. This is especially true when using routines like GetMem.
Some types always give the size of a pointer, since they are just that - pointers to where the type data is stored. For example, strings.
Use the InstanceSize method to get the size of an object.
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| Related commands |
| Length |
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Return the number of elements in an array or string |
| SetLength |
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Changes the size of a string, or the size(s) of an array |
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| Example code : Show the sizes of some data types and variables |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
// The System unit does not need to be defined
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
intNumber : Integer;
extNumber : Extended;
sentence : string;
begin
// Display the sizes of a number of data types
ShowMessageFmt(' SizeOf(Integer) = %d',[SizeOf(Integer)]);
ShowMessageFmt('SizeOf(intNumber) = %d',[SizeOf(intNumber)]);
ShowMessageFmt(' SizeOf(Extended) = %d',[SizeOf(Extended)]);
ShowMessageFmt('SizeOf(extNumber) = %d',[SizeOf(extNumber)]);
// String types and variables are pointers to the actual strings
sentence := 'A long sentence, certainly longer than 4';
ShowMessageFmt(' SizeOf(string) = %d',[SizeOf(string)]);
ShowMessageFmt(' SizeOf(sentence) = %d',[SizeOf(sentence)]);
end;
end.
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| Hide full unit code |
SizeOf(Integer) = 4
SizeOf(intNumber) = 4
SizeOf(Extended) = 10
SizeOf(extNumber) = 10
SizeOf(string) = 4
SizeOf(sentence) = 4
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| Example code : Use GetMem to allocate storage for ten records |
type
TRecord = Record
name : string[10];
age : Byte;
end;
var
recStorage : PChar;
begin
// Show the size of our record type
ShowMessageFmt(' SizeOf(TRecord) = %d',[SizeOf(TRecord)]);
// Allocate storage for ten of these records
GetMem(recStorage, 10 * SizeOf(TRecord));
end;
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| Show full unit code |
SizeOf(TRecord) = 12
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