Changing compiler in Qt

Question

How to change compiler (GCC) in Qt? I've installed GCC 4.4 and 4.6. At the momment Qt uses 4.4 but I'd like it to use 4.6. How to do it?

Answer 1

In the build sequence it may have a qmake command like qmake YourProject.pro -r -spec linux-g++-64 the choice of the tool chain is done in the spec file here linux-g++-64. Your will find this file in path-to-the-sdk/qt/mkspecs/linux-g++-64 (you get the concept right?)... If you open the spec file you will see that it includes the linux spec and the g++ spec.

One solution is to copy the g++ spec file and rename it g++-4.6 for example edit it and change :

QMAKE_CC = gcc
QMAKE_CXX = g++

to :

QMAKE_CC = gcc-4.6 
QMAKE_CXX = g++-4.6

Idem for the linux-g++-64 it can be copied to linux-g++-4.6-64 and modify the include(...) command to include your new g++-4.6 file.

Finally build your project with qmake YourProject.pro -r -spec linux-g++-4.6-64.

I hope it's clear :) ...

Answer 2

I realise I am very late for the party but on Linux it is as simple as follows:

qmake -makefile <your-project.pro> -spec linux-clang

On my system, all sorts of different mkspecs are available at:

/usr/lib/x86_64-linux-gnu/qt5/mkspecs