Re: Dynamic class loading
vlbel@mail.ru wrote:
I'm trying to do the following:
1) The main program consists of
------------ a.h ------------
class A
{
public:
virtual ~A(){}
virtual void b();
};
------------ a.cpp -----------
#include "a.h"
void A::b()
{}
------------ main.cpp ------------
#include <dlfcn.h>
#include <iostream>
using namespace std;
int main()
{
void* handler = dlopen( "../lib/lib.so", RTLD_LAZY );
if( !handler )
{
cout << "Bad" << endl;
cout << dlerror() << endl;
Neither 'dlopen' nor 'dlerror' are standard C++ or C functions.
They aren't topical here (if you think they are essential to
your question, which I believe they are).
}
}
-----------------------------------
2) Loadable library:
---------------- lib.cpp --------------------
#include "a.h"
class C : public A
{
public:
C() : A(){}
};
extern "C" A* maker()
{
return new C();
}
----------------------------------------------
Compiles ok (gcc 4.1.0, SUSE Linux), but running the program I get:
../lib/lib.so: undefined symbol: _ZN1A1bEv
What's the matter? nm shows that symbol is defined (in a.o)
Your question has no answer in terms of C++ _langauge_. You need to
ask in the newsgroup where dynamic linking is on topic (most likely
the newsgroup for your OS). Also, since you're using 'gcc' you might
consider posting to 'gnu.g++.help' or 'gnu.gcc.help' since they know
more about how the compiler/linker resolves symbols in such cases.
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask