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hi

is there a neccesity for the Qapplication(....) to be in the main .cpp.
Wht happens in the case of using a non gui based application where in the bootom layer starts the
entire operation.
u want the Qapplication running but it cannot be the main.cpp.

Is there a work around, if so plz let me know.
It would be of great help if somebody could paste the code for this kind of scenario.

Currently the Qapplication is declared in say class UI{
public : Qapplication(...)

The error is : request for setMainwidget in this->UI::a->(int , char**) which is of the non aggregate <unknown type>

One more thing wht exactly does the a->exec() function do.
Is it a must and can it be done away with

could u kindly post a sample code

of how u go a bout creating an instance of qapplication in a place other than main.cpp file.

i have been trying to do it, i haven't succeded.

thanks in advance

code which u have pasted above compiled all right but gave a segmentation fault when i ran it.
It said error in parameters passed to qapp(0,0,false).

Then wht i did was change the prototype of the foo function and passed the main command line arguments to the function.

FOO.CPP
// Qt includes
#include <qapplication.h>
# include<iostream>

using namespace std;
// local includes
#include "foo.h"

int foo(int v,char ** c)
{



QApplication app(v,c,TRUE); // false -> without GUI
cout<<"Qpp starting"<<endl;
app.exec();
return 0;

}


FOO.H
int foo(int,char **);



MAIN.CPP
#include <qapplication.h>
#include<iostream>
#include "form1.h"

#include <qapplication.h>



#include "foo.h"
using namespace std;
int main(int argc,char**argv)
{
cout<<"main starting:";
cout<<foo(argc,argv);

return 0;
}


I get output as
main starting: qpp starting (these are the 2 outputs which i had given to debug the prog, refer code)
then code hangs , i have to press control C to exit the program.


is there a prob exec();

i use qt version 3.2.3 , is it a stable release or is there something wrong i am doing int he way
i have implemented the code.

kindly help

Also by non gui based application i meant a middle layer which would instantiate the gui layer which has a class called GUIMANAGER, say which manages the gui screens, connection between screens etc .
by non gui i didn't refer to a console applicaiton. i need the screen shots to ??
Is ther a work around??
in the above code i have wantedly set the parameter as TRUE in instantiation of qapplication
because of the above reason.

hi
argv[0] i printed i get the file name(./qap is my prog name)
argc returns a value pf 1
But when i try to print argv[1] as well as argv[2] (They don't have anyting stored in them) before the call to foo(.. , ..)
My prog hangs.it doesn't even call the foo function.

I tried the same thing in another example prog, the prog doesn't hang but anywhere else i use cout , i don't get the output in the console.


SO wht could be the problem with my code if not for NULL pointer.



************************************************************************************************
Wht i am trying to do is to build a minimalistic GUI with 4 forms, (which are working fine).
I have a lower layer from which i have to call my gui prog, and as i navigate through the forms
each command say a push button in the form would probably transfer execution to the lower layer.

Basically the main should lie in the lower layer and the GUIfunctionality is separate.


I have a UIMAIN class whose interfaces the lower layer calls.
I don't want the GUI to start the entire applicaiton, basically code should run even without the GUI jus remove it and show in console.
I hope i have made my self clear.

Basically qapplication shouldn't be in the main.cpp

****************************************************************************************************

I encountered a peculiar problem when i ran the make command(all of a sudden)
I don't even know if i should tell it here, hmm its relevance??

This is wht i got as an output jus before the compilation got over.

g++ -o qap .obj/foo.o .obj/main.o .obj/form1.o .obj/moc_form1.o -L/usr/lib/qt-3.2/lib -L/usr/X11R6/lib -lqt-mt -lXext -lX11 -lm
**You have new mail in /var/spool/mail/root**

The statement enclosed within the ** ........**

is it because of a virus, linux OS prob, qt, qmake ............

i got this when i did make for both my prog and an example prog from the tutorial.

for 3 to 4 makes this came as an output
and all of a sudden it didn't reappear.
******************************************************************************************************
I am new to Linux as well as Qt. so i am sorry if i have posted irrelevant messages.
kindly reply.

hi
argv[0] i printed i get the file name(./qap is my prog name)
argc returns a value pf 1
But when i try to print argv[1] as well as argv[2] (They don't have anyting stored in them) before the call to foo(.. , ..)
My prog hangs.it doesn't even call the foo function.

I tried the same thing in another example prog, the prog doesn't hang but anywhere else i use cout , i don't get the output in the console.


SO wht could be the problem with my code if not for NULL pointer.



************************************************************************************************
Wht i am trying to do is to build a minimalistic GUI with 4 forms, (which are working fine).
I have a lower layer from which i have to call my gui prog, and as i navigate through the forms
each command say a push button in the form would probably transfer execution to the lower layer.

Basically the main should lie in the lower layer and the GUIfunctionality is separate.


I have a UIMAIN class whose interfaces the lower layer calls.
I don't want the GUI to start the entire applicaiton, basically code should run even without the GUI jus remove it and show in console.
I hope i have made my self clear.

Basically qapplication shouldn't be in the main.cpp

****************************************************************************************************

I encountered a peculiar problem when i ran the make command(all of a sudden)
I don't even know if i should tell it here, hmm its relevance??

This is wht i got as an output jus before the compilation got over.

g++ -o qap .obj/foo.o .obj/main.o .obj/form1.o .obj/moc_form1.o -L/usr/lib/qt-3.2/lib -L/usr/X11R6/lib -lqt-mt -lXext -lX11 -lm
**You have new mail in /var/spool/mail/root**
(this was not a valid directory)

The statement enclosed within the ** ........**

is it because of a virus, linux OS prob, qt, qmake ............

i got this when i did make for both my prog and an example prog from the tutorial.

for 3 to 4 makes this came as an output
and all of a sudden it didn't reappear.
******************************************************************************************************
I am new to Linux as well as Qt. so i am sorry if i have posted irrelevant messages.
kindly reply.

i know tht the code is hung because i output the return value of the "foo funciton"
which apparently never is not printed because the foo function never executes the return
statement as the prog is getting struck in the app.exec()

/* the foo.cpp*/
QApplication app(v,c,TRUE); // false -> without GUI
cout<<"Qpp starting"<<endl;
app.exec();
return 0;

Implementing the 2nd way is something way beyond wht i can achieve in the time i have which is about a week.

Thats y i wanted to instantiate qapplication else where and have a middle layer main.cpp which instantiates the UIManager, and hence qapplication.
if at all i need to run gui the only separately change i would have to do is
to write a main for the gui alone.

More ever i feel this is a much easier way than the other 2 suggested becoz of the learning curve involved( i am new to threads also)
The first way of having the gui run in a thread and the bottom layer run in a another - i ll look into it.



I am still curious, i would like to know wht went wrong with the

code posted by Mr anda_skoa- it gave me a segmentation fault.
The modified code(changes which i incorporated), y does it hang when

app.exec() is called.

I would be more satisfied if the problem is found out and then a suitable solution arrived at rahter than have a work around.

if anybody has tried instantiating qapplication else where than the main file
please post a working code.
thanks in advance.