使用QProcess的G ++ makefile命令

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 -IC:\\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 -IC:\\QtDir\\include -LC:\\Qtdir\\lib -l Qt C:/Documents/ED30/dialog.cpp")