Attributes files

[Jeronimo]

Hi i want to take attribute some my files:
SetFileAttributes("C:/file.txt", FILE_ATTRIBUTE_NORMAL);

But when i try show me these error:
:74: error: 'FILE_ATTRIBUTE_HIDDEN' was not declared in this scope
SetFileAttributes("C:/file.txt", FILE_ATTRIBUTE_HIDDEN);
error: 'SetFileAttributes' was not declared in this scope
SetFileAttributes("C:/file.txt", FILE_ATTRIBUTE_HIDDEN);

                                  ^~~~~~~~~~~~~~~~~~~~~

Edit: Question unrelated to Qt -- @Wieland