Delphi in a Nutshell

Name

SetString Procedure

Syntax

procedure SetString(var Str: string; Buffer: PChar; Length: Integer);

Description

The SetString procedure sets the length of Str to Length, then copies Length characters from Buffer to the string. SetString is not a real procedure.

Tips and Tricks

• If Str is a long string, SetString always allocates a new string, so Str is set to a unique string.

• Str can be a ShortString, in which case the Length must be less than 256.

• Buffer can be nil, in which case the string length is set, but its contents are left uninitialized. In the case of a ShortString, the previous string contents are left untouched.

Example

// Given an instance or module handle, return the corresponding
// filename. Note that Delphi will automatically convert
// a PChar to a string, but it must scan the PChar to learn
// its length. GetModuleFileName returns the length, so there is
// no need to let Delphi rescan the string.
function GetModuleName(Instance: THandle): string;
var
  Len: Integer;
  Buffer: array[0..MAX_PATH] of Char;
begin
  Len := GetModuleFileName(HInstance, Buffer, SizeOf(Buffer));
  SetString(Result, Buffer, Len);
end;

See Also

AnsiString Type, SetLength Procedure, ShortString Type, String Keyword, WideString Type