@SGaist said:

Hi,

What should the output look like ?

if is something like "$0.0"

ui->label->setText(QString("$%1").arg(APP_VERSION, 2, 'f', 1);

would be way simpler and clean

Sorry for the late reply.
No, the result should be ''0.0": the $ is used only for the variable like in bash.
I just wanted to replace $APP_VERSION string inside label by 0.0 using BASH_REPL_WCS.
is there anything wrong with the preprocessor? if not, how to do it using the high-level Qt method?