How does Qt Creator compose the invocation of gcc/g++?
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Cross compiling an app for arm in Qt 5.15 with Qt Creator 4.5.2, i am trying to remove the -O2 optimization flag from the relase build g++ call; i need to remove it as i want to test a build using -Ofast instead, but the problem is that my flag gets inserted before the already present one and is therefore ignored.
I have checked all the Environment variables set for my project build, and removed "-O2" from all those which contained it; the variables which used to contain the flag are the following:
CXXFLAGS
QMAKE_CXXFLAGS
OE_QMAKE_CXXFLAGSI have also added the following to my project file
QMAKE_CXXFLAGS -= -O2 QMAKE_CXXFLAGS += -Ofastand i can see the -Ofast flag is added to the compiler call, which follows
arm-poky-linux-gnueabi-g++ -mthumb -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a7 --sysroot=/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi -c -pipe --sysroot=/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi -Ofast -O2 -Wall -Wextra -D_REENTRANT -fPIC -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x060000 -DQT_NO_DEBUG -DQT_PDFWIDGETS_LIB -DQT_WIDGETS_LIB -DQT_PDF_LIB -DQT_GUI_LIB -DQT_SERIALPORT_LIB -DQT_CORE_LIB -I. -I/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi/usr/include/QtPdfWidgets -I/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi/usr/include/QtWidgets -I/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi/usr/include/QtPdf -I/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi/usr/include/QtGui -I/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi/usr/include/QtSerialPort -I/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi/usr/include/QtCore -I. -I. -I/opt/eng-imx-fb/5.10-gatesgarth/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi/usr/lib/mkspecs/linux-oe-g++ -o main.o main.cppI couldn't find in the Qt Creator documentation how is this call to g++ created, for instance i also don't understand where all the includes are specified, as there is no environment variable associated to them, just this line
QT += core gui widgets serialport pdfwidgetsat the top of the project file.
Can anyone point me to the relvant docs, if such exist, or provide clues on where to look next?
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This has nothing to do with QtCreator but with your build system (qmake in your case). All qmake vvariables can be found here: https://doc.qt.io/qt-6/qmake-variable-reference.html
Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
Visit the Qt Academy at https://academy.qt.io/catalog -
This has nothing to do with QtCreator but with your build system (qmake in your case). All qmake vvariables can be found here: https://doc.qt.io/qt-6/qmake-variable-reference.html
@Christian-Ehrlicher Thanks! I was able to solve my issue with this.
As you may have guessed, i am not completely aware of what goes on behind the scense with this IDE, and also not very familiar with make/cmake/qmake in general. -
J JeKK666 has marked this topic as solved on
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@Christian-Ehrlicher Albeit i was able to solved the specific issue i was having, is there a way to determine what the call to the compiler will look like?
Can i find this somewhere in the IDE, or the compiler call is simply a result of what qmake does when parsing the .pro file? -
You can take a look into the generated Makefile
