after compilingreceiving QtFatalMsg

[quickNitin]

After doing all modifications , code fixing at compilation i am getting



qgis: symbol lookup error: /usr/lib/qgis/libqgis_plugin_va.so: undefined symbol: _ZN12vARubberBandC1EP12QgsMapCanvas

resulting in QtFatalMsg.
I couldn't found the reason for this. I had checked my code but it looks normal.

[jacek]

Does your plugin use classes from the application?

[quickNitin]

yes, they do through inheritance which is inevitable.
Here vARubberBand class is defined at same level in heirarchy as plugin ( same placer also ).
I have a data member pointer to vARubberBand and create a object of it in constructor.



//! tool for drawing polygons
class vARubberBand *rubberBand;
//! add point to this list
std::vector<QgsPoint> mPoints;
//!

[jacek]

Either add -rdynamic to application's linker flags, or move all common classes to separate library and link both the application and the plugin with it. Note that the first solution won't work under windows.

Another solution is to use only interfaces in the plugin.

[quickNitin]

i followed first method but still receiving symbol lookup error. i have also tried declaring vARubberBand class in different namespace, just to avoid chance of redeclaration, but not succeeded.

[jacek]

How did you implement vARubberBand::vARubberBand(QgsMapCanvas*)?

[quickNitin]

vARubberBand::vARuberBand(QgsMapCanvas *mapCanvas):QgsMapCanvasItem(mapCanvas)
{
mPoints.push_back(QgsPoint());
QColor color=new QColor(Qt::LightGray);
QColor fillColor(color.red(),color.green(),color.blue(),6 3);
mPen.setColor(QColor(Qt::LightGray));
mBrush.setColor(fillColor);
mBrush.setStyle(Qt::solidPattern);
}

[quickNitin]

i am attaching in question code here

[jacek]

-rdynamic should go to compiler flags, not linker ones.

[quickNitin]

here i am presenting some part of makefile



CC = gcc
CCDEPMODE = depmode=gcc3
CFLAGS = -g -O2 -rdynamic
CPP = gcc -E
CPPFLAGS =
CXX = g++
CXXCPP = g++ -E
CXXDEPMODE = depmode=gcc3
CXXFLAGS = -g -O2 -rdynamic
CYGPATH_W = echo
.
.
.
CXXCOMPILE = $(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) \
$(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS)
.
.
.
.cpp.o:
if $(CXXCOMPILE) -MT $@ -MD -MP -MF "$(DEPDIR)/$*.Tpo" -c -o $@ $<; \
then mv -f "$(DEPDIR)/$*.Tpo" "$(DEPDIR)/$*.Po"; else rm -f "$(DEPDIR)/$*.Tpo"; exit 1; fi
# source='$<' object='$@' libtool=no \
# DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) \
# $(CXXCOMPILE) -c -o $@ $<

[quickNitin]

vARubberBand::vARuberBand(QgsMapCanvas *mapCanvas):QgsMapCanvasItem(mapCanvas)
{
mPoints.push_back(QgsPoint());



found one typing error . It should had been vARubberBand ( 2 b) but i put vARuberBand(). compiling whole code again.

Shouldn't compiler detect it and atleast issue a warning

[jacek]

Shouldn't compiler detect it and atleast issue a warning
Yes, but only if the error was only in implementation.

[wysota]

-rdynamic should go to compiler flags, not linker ones.

AFAIR it should go to linker flags (it's the same as --export-dynamic).

[jacek]

it should go to linker flags (it's the same as --export-dynamic).
It is a compiler option, which tells it to pass --export-dynamic to the linker.

[quickNitin]

back to square one, after doing all these corrections again same error appears
:(
.

[wysota]

Did you try with exporting the symbols used in the plugin into a separate library?

[quickNitin]

no i hadnot. i don't know how to do that.

[wysota]

Create a subproject with lib template and put all the classes and functions you want to use in plugins (and remove them from the main project). Then tell the main project to link with the library (for example using LIBS+=-L pathtosubproject -lnameoflib). Do the same with all the plugins (I mean link them against the newly created library). Remember that this library has to be found by the dynamic loader when you start your main app (you can use LD_LIBRARY_PATH env variable to do that).

[quickNitin]

i will try to follow the steps.