[Qt-interest] Using -isystem for Qt includes

[Harri Porten]

Hi!

On Wed, 17 Nov 2010, Karl Krach wrote:

> I have the problem, that I want to use with the GCC 4.4.5 the
> -Wconversion flag. But when I use it, I get a big amount of qt
> warnings. According this stack overflow article [1], I only have to
> include the qt headers with -isystem instead of -I. (@qt guys - this
> would be a nice improvement for the next versions!)
>
> How can I tell qmake, to generate Makefiles with -isystem ?

If portability of your code is a concern better be careful.

Because of the same -Wconversion problem we had been using -isystem for a 
few years now. After a bug report by a customer I dropped it again, 
though.

Note that the switch not only changes the treatment of headers but also 
the inclusion order. On the customer's system a wrong system header got 
picked up causing some wchar_t error. I can check our support archive if 
more details are of interest.

On Mac OS X there were also problems which might have been due to the same 
cause.

Harri.