QFile, QDir, QXmlStreamWriter and other classes from QtCore in plain C++ project.

[QLab]

Hi,

It is possible to use classes from QtCore, especially QFile, QFileInfo, QDir, QXmlStreamWritter, QXmlStreamReader, QMimeDatabase, QMimeType and some other in plain c++ project without any problems?

Then i only need QtCore5.dll, i am right?

[mrjj]

Hi
In theory yes.
But you might need platforms plugin too.

Should be fast to test.

[QLab]

Ok, but what with signals and slots?

When some Qt classes from QtCore emit signal, and in my project I do not have QApplication instance, it will not be a problem?

[mrjj]

Yes it will. you need to supply event loop for signals to work.
http://stackoverflow.com/questions/12718296/is-there-a-way-to-use-qt-without-qapplicationexec

I think Qt::DirectConnection might work without event loop.

Can I ask why you want to use Qt and then not?
You could get nice file handling with pure c++and
xml with pugixml and have no dlls what so ever.

[QLab]

I prefer Qt classes for filesystem / xml because I already have some code which use this classes but in Qt project.

I can use boost for filesystem / xml ( propertytree? ), but then I also need dll but from boost so it nothing changes.

"You could get nice file handling with pure c++"
I think that this is not possible ;)

[mrjj]

@QLab
Ok. but why not just use it ?
and not worry if 1 or 2 dlls?
But yes, if you cut back on what class you use,
you should be able to cut some of the DLLS too.

C++ io not so bad. (IMHO) :)

        list data;
        string line;       
        ifstream myfile ("test.txt");
        if (myfile.is_open())    {
            for(line; getline(myfile, line);){
                data.push_back(line);
            }
            myfile.close();
        }

[QLab]

It is more complicated ;)

One example - detect mime type for file?
And many more which using Qt is simple but without Qt can take much more time.

I ask because sometimes simple task can works but later when i writed more code i can make troubles and then it will horrible.
Maybe someone know about problems using QtCore in plain c++ project. Only that ;)

I do not worry about dlls, but i do not want segfault or crash when i run my application which using some Qt classes in plain c++ project.

[mrjj]

@QLab
Ok. I see your point.
Well I don't think you can really get in trouble using only core.
But with no default event loop, you might get a few surprises. :)
Good luck

[QLab]

"But with no default event loop, you might get a few surprises"

Oh you know somethink more? ;) Please tell me ;)
I will have a trouble even if i do not connect signals?

[mrjj]

@QLab
HI
No No :) It's just that Qt uses signals
all over so some functions might use a signal to inform you of something or
two Qt objects might use signal internally.

But currently I made a small console project using QFile and to my surprise
it ask for no DLL when i click it, so i'm a bit ??:)

[mrjj]

Hi
I must do something wrong as for console app with Qfile it wants
(win 7 , mingw compiler)
icudt52.dll
icuin52.dll
icuuc52.dll
libgcc_s_dw2-1.dll
libstdc++-6.dll
libwinpthread-1.dll
Qt5Cored.dll
on a clean machine (virtual)
Not as tiny as i had hoped for :)