Can not call application function from shared library. Unresolved symbol error

zim32

Hi all.

I am trying to make a shared library, some sort of plugin, and I want this library to call some functions from my main app.
Library code is (simplified):

#include "../../core/plugin.h"
#include "iostream"
#include "objmeshloader.h"

static void register_plugin(zim::AppContainer *container)
{
    container->getMeshLoader()->registerLoader();
    std::cout << "Registering plugin objloader for app version: " << container->getAppMajorVersion() << std::endl;
}

When I try to load it using QLibrary it gives me error:

Error: Cannot load library libobjloader.so.1.0.0: undefined symbol: _ZN3zim12AppContainer13getMeshLoaderEv

    QLibrary lib(filePath);
    lib.setLoadHints(QLibrary::ResolveAllSymbolsHint);

    if (!lib.load()) {
        qFatal("Unable to load plugin %s. Error: %s", qUtf8Printable(filePath), qUtf8Printable(lib.errorString()));
    }

When I dump symbols it seems that everything is OK

nm -g  app | grep _ZN3zim12AppContainer13getMeshLoaderEv
000000000000738a T _ZN3zim12AppContainer13getMeshLoaderEv

nm -g  plugins/libobjloader.so.1.0.0 | grep _ZN3zim12AppContainer13getMeshLoaderEv
U _ZN3zim12AppContainer13getMeshLoaderEv

Why it can not link library?

zim32

So I solved thi issue.

QMAKE_LFLAGS += -export-dynamic

sierdzio

@zim32 said in Can not call application function from shared library. Unresolved symbol error:

libobjloader.so.1.0.0

That's your whole file path? Is the working dir the same as location of that library, then?

zim32

Library is located under ./plugins/ directory of my app. It works fine (because I was able to load library before calling container->getMeshLoader() function)

zim32

It seems I can't call any function defined if my main app.

F.e. if I declare some simple function in plugin.h file

extern "C" {
void some_test_func();
}

and then define it in my main.cpp

void some_test_func() {
    qDebug("some_test_func called");
}

Trying to call it from shared library gives me undefined symbol: some_test_func

zim32

So I solved thi issue.

QMAKE_LFLAGS += -export-dynamic