| Description |
The FreeMem procedure frees up memory storage used by a variable MemoryPointer.
You can optionally specify the MemorySize to be freed. However, you must specify the size allocated in the first place.
If the variable is nil then nothing happens.
If the variable invalidly points to memory (maybe it has already been freed), then an EInvalidPointer exception is thrown.
If the memory contains references to memory based variables, you must call Finalize before FreeMem.
FreeMem is the counter command to GetMem.
Ideally, you should use New and Dispose instead of GetMem and FreeMem. It avoids the need to call Finalize.
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| Related commands |
| Dispose |
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Dispose of storage used by a pointer type variable |
| GetMem |
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Get a specified number of storage bytes |
| New |
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Create a new pointer type variable |
| ReallocMem |
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Reallocate an existing block of storage |
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| Example code : A simple exampl of using GetMem and FreeMem |
// 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
charPtr : PChar;
begin
// Allocate storage for 4 characters
GetMem(charPtr, 4 * SizeOf(Char));
// Assign to these characters
charPtr^ := 'A';
Inc(charPtr);
charPtr^ := 'B';
Inc(charPtr);
charPtr^ := 'C';
Inc(charPtr);
charPtr^ := #0; // String terminator
// Now display these values
Dec(charPtr, 3);
ShowMessage('Characters stored = '+charPtr);
// Now free the memory for these characters
FreeMem(charPtr);
end;
end.
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| Hide full unit code |
Characters stored = ABC
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