function MsgBox(const Text: String; const Typ: TMsgBoxType; const Buttons: Integer): Integer;
TMsgBoxType is defined as:
TMsgBoxType = (mbInformation, mbConfirmation, mbError, mbCriticalError);
Supported flags for Buttons are:
MB_OK, MB_OKCANCEL, MB_ABORTRETRYIGNORE, MB_YESNOCANCEL, MB_YESNO, MB_RETRYCANCEL, MB_DEFBUTTON1, MB_DEFBUTTON2, MB_DEFBUTTON3, MB_SETFOREGROUND
Possible return values are:
IDOK, IDCANCEL, IDABORT, IDRETRY, IDIGNORE, IDYES, IDNO
MsgBox('Hello.', mbInformation, MB_OK);