G++ makefile command with QProcess - c++

Question

I'm trying to generate a .exe file with g++ compiler. I tried multiple ways without sucess.
1) QString program = "C:/Strawberry/c/bin/g++";
QStringList arguments;
arguments << "g++ -o dialog C:/Documents/ED30/dialog.cpp";
QProcess process;
process.start(program, arguments);
process.waitForFinished(-1);
2) QProcess::execute("g++ -o dialog2 C:/Documents/ED30/dialog.cpp");
3) QProcess::execute("g++ C:/Documents/ED30/dialog.cpp -o dialog2");
Everytime I have the same error message :
"In file included from C:/Documents/ED30/dialog.cpp:1:0:
C:/Documents/ED30/dialog.h:4:19: fatal error: QDialog: No such file or directory
compilation terminated."
Or sometimes nothing happens.
I'm using Qt 5.7 with MinGW on windows 8.1
EDIT:
So after discussing the issue with members, I did some progress.
Best code until now is :
system("g++ -o dialog2 -I C:/Qt/5.8/mingw53_32/include -I C:/Qt/5.8/mingw53_32/include/QtGui -I C:/Qt/5.8/mingw53_32/include/QtCore -I C:/Qt/5.8/mingw53_32/include/QtWidgets -L C:/Qt/5.8/mingw53_32/lib C:/Documents/ED30/dialog.cpp");
But this indicats me that MinGW isn't a c++ 11 compiler and it suggests me to write "-std=c++11 or -std=gnu++11" in the command-line in order to update the Compiler. After typing it in the compiler, the following error appears: "Unknow command".
I tried with Qt 5.7 and 5.8 without success.
A solution guys ?

Answer 1

It seems the code you are trying to compile dialog.cpp makes use of Qt (QDialog in particular).
When you run g++ -o dialog2 C:/Documents/ED30/dialog.cpp, g++ fails because it cannot find where Qt header and library files are.
The minimal command line to make it work would be:
g++ -o dialog2 -I<PathToQtheaders> -L<PathToQtLibraries> -lQt5Core -lQt5Gui -lQt5Widgets C:/Documents/ED30/dialog.cpp
You might need to add some extra libraries depending on what you code needs. Note that you cannot use Q_OBJECT macro if you just compile it like that (without calling moc etc.).
Tip: Look at the commands generated by qmake on a standard Qt project.
Extra tip: You can use QLibraryInfo::location() to get Qt installation paths.
Also your first example should be:
QString program = "C:/Strawberry/c/bin/g++";
QStringList arguments;
arguments << "-o" << "dialog" << "C:/Documents/ED30/dialog.cpp";
QProcess process = "g++";
process.start(program, arguments);
process.waitForFinished(-1);

Answer 2

I think you are missing the include directory of your Qt headers.
QProcess::execute("g++ -o dialog -I C:\QtDir C:/Documents/ED30/dialog.cpp");
QtDir is the actual location of the Qt Headers on your system like C:\Qt\include
You may also have trouble linking. The whole command is:
QProcess::execute("g++ -o dialog -I C:\QtDir\include -L C:\Qtdir\lib -l Qt C:/Documents/ED30/dialog.cpp")