Qt-interest Archive, March 2002
Maiantaining a variable value throughout the application
Message 1 in thread
Hello all,
I am having the selected item of combo box in a variable
strLanguage..
I have to pass this variable to the form2.
I have used the variable as
static char strLanguage[20] in form1.
Then i have used extern char strLanguage in form2.
I displayed this variable in form2 as printf("\n%s",strLanguage)
When i compile the following error is coming.
In function `Form2::Form2(QWidget *, char const *, bool, unsigned int)':
undefined reference to `strLanguage'
How to refer the variable.
On Wed, 20 Mar 2002, Mariusz Lotko wrote:
> On Wed 20. March 2002 12:09, you wrote:
> > Hi Konrad,
> >
> > I am not having any interface for both the forms.
> > What i am doing is i am having one application.
> > In this applicaiton, i have defined the form2.
> > Then in form1, whenever the ok button is clicked, in the click event of
> > this button, i am closing the first form and since i have defined form2 in
> > the main appliction, it will be automatically invoked.
> > So i am not having any interface.
> >
> > How can i get the variable as i have said earlier from the combobox to the
> > next form.
>
> void QComboBox::activated ( int index ) [signal]
>
> Read the doc about signal/slot mechanism in Qt.
>
>
--
[ signature omitted ]
Message 2 in thread
You are definining your global as 'static' when really it should not be
'static'. Static in non-member-variables means that it is not exported to
other compilation units, which is why you are getting a link error.
Just remove the keyword static and your variable should be visible from
all compilation units that are interested in it and that have that extern
declaration...
-Calin
On Thu, 21 Mar 2002, A.BalaSaraswathi wrote:
> Hello all,
>
>
> I am having the selected item of combo box in a variable
> strLanguage..
> I have to pass this variable to the form2.
> I have used the variable as
>
> static char strLanguage[20] in form1.
> Then i have used extern char strLanguage in form2.
> I displayed this variable in form2 as printf("\n%s",strLanguage)
> When i compile the following error is coming.
>
> In function `Form2::Form2(QWidget *, char const *, bool, unsigned int)':
> undefined reference to `strLanguage'
>
> How to refer the variable.
>
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> On Wed, 20 Mar 2002, Mariusz Lotko wrote:
>
> > On Wed 20. March 2002 12:09, you wrote:
> > > Hi Konrad,
> > >
> > > I am not having any interface for both the forms.
> > > What i am doing is i am having one application.
> > > In this applicaiton, i have defined the form2.
> > > Then in form1, whenever the ok button is clicked, in the click event of
> > > this button, i am closing the first form and since i have defined form2 in
> > > the main appliction, it will be automatically invoked.
> > > So i am not having any interface.
> > >
> > > How can i get the variable as i have said earlier from the combobox to the
> > > next form.
> >
> > void QComboBox::activated ( int index ) [signal]
> >
> > Read the doc about signal/slot mechanism in Qt.
> >
> >
>
>
Message 3 in thread
This is not related to Qt. You should find a C++ forum to ask your question.
On Wednesday 20 March 2002 11:26 pm, A.BalaSaraswathi wrote:
>
> I am having the selected item of combo box in a variable
> strLanguage..
> I have to pass this variable to the form2.
> I have used the variable as
>
> static char strLanguage[20] in form1.
What is form1? I am assuming that it is a class. Also, you should likely be
using a string or a QString instead of the C-style char[].
> Then i have used extern char strLanguage in form2.
> I displayed this variable in form2 as printf("\n%s",strLanguage)
> When i compile the following error is coming.
You should use cout instead of printf(). Also, you should refer to
strLanguage correctly, i.e. form1::strLanguage, assuming form1 is a class and
strLanguage is defined inside of it.
