Hello thanks for reply,
Yes ctc32 is an executable and args -i m for instrumentation multi-condition code coverage.
I added these lines to my project file.

CodeCoverage { CTC32 += ctc32 -i m } QMAKE_CC = CTC32$$QMAKE_CXX QMAKE_CXX = CTC32$$QMAKE_CXX

I really don't understand how to tell Qt creator to call ctc32 before calling g++ (or in other words ctc32 will call g++). I had a look on qmake Variable Reference but this is the only thing I got.

Thank you