From the February 2011 Issue of Prestwood eMag
Delphi Language Details:
Pascal and PChar Strings
Posted
21 years ago on 3/18/2003 and updated 12/12/2006
Take Away: Using Pascal and PChar strings in Delphi.
KB100160
ObjectPascal has two varieties of string variables: Pascal strings and Pchar strings. PChar strings are also known as null terminated strings because the last character in memory is always the null character (ASCII 0).
Using Pascal strings
The first character in memory is used to store the length of the string. Because this character is an unsigned short integer it is limited to 255 characters; unsigned short integers have a range from 0 to 255.
procedure TForm1.Button3Click(Sender: TObject);
var
sPascalType: String[20];
begin
sPascalType := 'Felina Prestwood';
ShowMessage(sPascalType);
end;
Using PChar strings
Here are some examples:
var
s: String;
or
var
s2: PChar;
for example, type in the following code.
procedure TForm1.Button4Click(Sender: TObject);
var
s1: String;
s2: PChar;
begin
s1 := 'Felicia Prestwood';
s2 := 'Felina Prestwood';
ShowMessage(s1);
ShowMessage(s2);
end;
1 Comments.
Share a thought or comment...
I've compiled my application in delphi 7. i received a warning that states Unsafe type 'PChar'..
what should i do?
KB Post Contributed By Mike Prestwood:
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