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Error Undefined reference when using shared lib

ad5xj

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1

Thursday, October 1st 2009, 6:01pm

Error Undefined reference when using shared lib

Hello everyone

I am having a problem converting a working project to separate shared libaries and application. I have created a shared libarary and added the code to make it a library:

In the library global:

Source code

 
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#include <QtCore/qglobal.h>

#if defined(OPENMODEM_LIBRARY)
#  define OPENMODEMSHARED_EXPORT Q_DECL_EXPORT
#else
#  define OPENMODEMSHARED_EXPORT Q_DECL_IMPORT
#endif


In the library public interface:

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#include "openModem_global.h"
//////  EXPORTED CLASS DEFINITION  //////
class OPENMODEMSHARED_EXPORT openModem : public QObject
{
    Q_OBJECT

public:
    openModem(QObject *parent=0);
    ~openModem();


When I try to use this library in the app I get this:

Error Undefined reference to _imp_ZN9openModemC1EP7QObject

What am I overlooking?
AD5XJ

Nicolas SOUCHON

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2

Friday, October 2nd 2009, 9:24am

need .pro files of both app and library to tell something

Huupke

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3

Friday, October 2nd 2009, 12:06pm

it seems that the lib is not loaded. Have you tried a static library or myabe a stub test function?

ad5xj

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4

Friday, October 2nd 2009, 7:19pm

Error Undefined reference when using shared lib

Here is the .pro code from both lib and app


Library .pro:

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TEMPLATE = lib 
DEFINES += OPENMODEM_LIBRARY
QT -= gui
CONFIG = qt thread warn_on debug
win32:CONFIG += dll windows
unix:CONFIG += shared x11
TARGET = openModem
MOC_DIR = moc
OBJECTS_DIR = obj
SOURCES += . . .

win32:SOURCES += . . .


HEADERS += . . .
win32:HEADERS += . . .

win32:LIBS += -lwinmm



Application .pro

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TEMPLATE = app 
TARGET = MultiQ
QT +=
DEPENDPATH = .
INCLUDEPATH = .
CONFIG = qt exceptions thread warn_on debug
win32:CONFIG += windows
unix:CONFIG += unix x11
MOC_DIR = moc
OBJECTS_DIR = obj
DESTDIR = debug
SOURCES += . . .

HEADERS += . . .

win32:LIBS += -L../openModem/openModem.dll
unix:LIBS += -llibopenModem.a
RESOURCES += application.qrc

Hope this helps
The application is a working application and all modules are the same as in the working app. The only difference is the one noted. I am missing something where the exported symbols are concerned. The linker finds my DLL but the symbols are not resolved.
AD5XJ

Nicolas SOUCHON

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Posts: 1,867

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5

Saturday, October 3rd 2009, 11:14am

RE: Error Undefined reference when using shared lib

try
Library .pro:

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TEMPLATE     = lib
TARGET       = openmodem
DEFINES     += OPENMODEM_LIBRARY

QT          -= gui

MOC_DIR      = moc
OBJECTS_DIR  = obj

SOURCES     += ...

HEADERS     += ...

win32: {
        SOURCES     += ...
        HEADERS     += ...
}

Application .pro

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TEMPLATE     = app
TARGET       = multiq

DESTDIR      = debug
MOC_DIR      = moc
OBJECTS_DIR  = obj

DEPENDPATH   = .
INCLUDEPATH  = .

SOURCES     += ...

HEADERS     += ...

RESOURCES   += application.qrc

LIBS        += -L../openmodem -lopenmodem

ad5xj

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6

Sunday, October 4th 2009, 7:53pm

Error Undefined reference when using shared lib

This yields more errors in every use of the library objects:

error: invalid use of undefined type `struct openModem'
AD5XJ

ad5xj

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7

Sunday, October 4th 2009, 8:16pm

Error Undefined reference when using shared lib

Problem solved!

There was a small typo error (lower case where upper case was needed) in the app code that references the objects.

Thanks for your help!
AD5XJ