Question

I have got a f2.cpp file

// f2.cpp
#include <iostream>

void f2()
{
    std::cout << "It's a call of f2 function" << std::endl;
}

I use cygwin with crosstool compiler gcc.

g++ -fPIC -c f2.cpp
g++ -shared -o libf2.so f2.o

I have got a libf2.so file. Now I want to call f2 function in f1 library (shared object too) libf1.so.

It’s a f1.cpp and i want take f1.so

// f1.cpp
#include <iostream>
void f1()
{
    std::cout << "f1 function is calling f2()..." << std::endl;
    f2();
}

How i must compile f1.cpp? I don’t want to use dlclose, dlerror, dlopen, dlsym…
Аt last i want to use f1.so in main.cpp as a shared object library too… without using use dlclose, dlerror, dlopen, dlsym. How I must compile main.cpp, when i will have a f1.so ?

// main.cpp
#include <iostream>
int main()
{
    f1();
    return 0;
}

Answer 1

declare f2() in a header file. and compile libf1.so similar to libf2.

Now compile main linking against f1 and f2.
It should look something like this
g++ -lf2 -lf1 -L /path/to/libs main.o