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shininglion/Makefile

Last active November 20, 2020 02:55
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when header and related shared lib mismatch
Raw
main.cpp
#include <dlfcn.h>
#include "testlib_old.h"
typedef A* (*create_obj_t)();
typedef void (*free_obj_t)(A* obj);
int main()
{
void* lib = dlopen("./libtestlib.so", RTLD_GLOBAL | RTLD_NOW);
create_obj_t create_obj_ptr = (create_obj_t)dlsym(lib, "create_obj");
free_obj_t free_obj_ptr = (free_obj_t)dlsym(lib, "free_obj");
A* obj = create_obj_ptr();
obj->print(); // It will call B::hidden
free_obj_ptr(obj);
dlclose(lib);
return 0;
}
Raw
Makefile
CC = g++ -O3
EXE = run
SO = libtestlib.so
all: $(SO) $(EXE)
$(EXE): main.cpp testlib.h
$(CC) -o $@ $< -ldl
$(SO): testlib.cpp testlib.h
$(CC) -fPIC -c $<
$(CC) -shared *.o -o $(SO)
clean:
rm -f $(EXE) $(SO) *.o
Raw
testlib.cpp
#include <stdio.h>
#include "testlib_new.h"
A* create_obj()
{
return new B();
}
void free_obj(A* obj)
{
delete obj;
}
void A::print()
{
puts("print function in A");
}
void A::hidden()
{
puts("hidden function in A");
}
void B::print()
{
puts("print function in B");
}
void B::hidden()
{
puts("hidden function in B");
}
Raw
testlib_new.h
#ifndef TESTLIB_H
#define TESTLIB_H
class A
{
public:
virtual ~A() = default;
virtual void hidden();
virtual void print();
};
class B : public A
{
public:
void hidden() override;
void print() override;
};
extern "C" {
A* create_obj();
void free_obj(A* obj);
}
#endif
Raw
testlib_old.h
#ifndef TESTLIB_H
#define TESTLIB_H
class A
{
public:
virtual ~A() = default;
virtual void print();
};
class B : public A
{
public:
void print() override;
};
extern "C" {
A* create_obj();
void free_obj(A* obj);
}
#endif
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