This one seems to pass compatibility, but you have to be careful.




If your code compiles and works in Delphi, this will also compile and work in Freepascal 32/64.

Nothing more is promised!

not so good decision coz result text can be longer than 1024 symbols

No! See MSDN. The limit is 1024 symbols. Even on 64 bit platforms.

pity. then better to use custom implementation without limits :(

Do you need it? Then change it! Pointer array is big enough.... ;)

But wsprintf will fail....

i made surrogate functions for me which works with text (%s only) and text with integers (%s, %d and %u substitutes) and replace it "by hands". And trying to use these functions where possible. (first part calculates length of final text, second makes replaces)

You can also use this trick from Andreas Hausladen:

function _FormatC(const Format: string): string; cdecl;
const
 StackSlotSize = SizeOf(Pointer);
var
 Args: va_list;
 Buffer: array[0..1024] of Char;
begin
 // va_start(Args, Format)
 Args := va_list(PAnsiChar(@Format) + ((SizeOf(Format) + StackSlotSize - 1) and not (StackSlotSize - 1)));
 SetString(Result, Buffer, wvsprintf(Buffer, PChar(Format), Args));
end;

const // allows us to use "varargs" in Delphi
 FormatC: function(const Format: string): string; cdecl varargs = _FormatC;

procedure TForm1.Button1Click(Sender: TObject);
begin
 MsgOk(FormatC('%s %03d', 'Hallo', 3));
end;

procedure TForm1.Button1Click(Sender: PObj);  // <smile>
begin
MsgOk(FormatC('%s %03d', 'Hallo', 3));
end;

I used Format ONLY because it is already present in Windows API (wsprintf), so calling it is cheaper then creating several formatting functions. It is useful to make some number-to-string conversions like %.03d (gives 002, not 2). In any other case it is cheaper to create several small functions like