AS. Nevermind. Had wrong gut feeling about continue on while/repeat loops. Made fool of myself :-)
See the commented line. If i uncomment it - compilation goes okay. If i keep it commented, then warning is given about undefined result. It seems compiler fails to account for pseudo-procedures like Break and Continue.
Is it happenning with prior Delphi versions ? Is there QC for it ?
//returns 0 or win32 error code
function TfmMain.callQDN(DeviceName: string;
out buff: string): DWORD;
const len_step = 8192;
var res, len, err: DWORD;
lpDeviceName: PChar;
begin
SetLength(buff, len_step);
len := Length(buff);
lpDeviceName := nil;
if DeviceName>'' then lpDeviceName := @DeviceName[1];
repeat
Res := QueryDosDevice(lpDeviceName, @buff[1], len);
if Res = 0 then begin
err := GetLastError;
// Result := err;
if err = ERROR_INSUFFICIENT_BUFFER then begin
len := len_step + len;
SetLength(buff, len);
continue;
end;
Result := err;
end else begin
Result := 0;
SetLength(buff, res); // res+1 ?
end;
until (Result = 0);
end;