common.c

int get() {
  puts("I'm get function of libbar");
  return 100000;
}

common.c

int get() {
  puts("I'm get function of libfoo");
  return 42;
}

compile.sh

#!/bin/sh
(cd libfoo && make)
(cd libbar && make)
gcc -o loader test_dyld.c

./loader

gistfile1.txt

><

main.c

int get();

int get_answer(){
  puts("I'm libbar and call get()");
  return get() + 1;
}

main.c

int get();

int get_answer(){
  puts("I'm libfoo and call get()");
  return get() + 1;
}

Makefile

libbar: main.o common.o
	gcc -dynamic -bundle -g -fPIC -o libbar.bundle $^ -Wl,-flat_namespace -fPIC

%.o : %.c
	 gcc -g -fPIC -c -o $@ $^

clean:
	rm -f *.o *.bundle

Makefile

libfoo: main.o common.o
	gcc -dynamic -bundle -g -fPIC -o libfoo.bundle $^ -Wl,-flat_namespace -fPIC

%.o : %.c
	 gcc -g -fPIC -c -o $@ $^

clean:
	rm -f *.o *.bundle

test_dyld.c

#include <dlfcn.h>
#include <stdio.h>

int load_and_call(const char* lib){
  void* handle = dlopen(lib, RTLD_GLOBAL | RTLD_LAZY);
  printf("error=%s\n", dlerror());

  int(*f)(void) = dlsym(handle, "get_answer");
  if(f != NULL){ printf("ret = %d\n", f()); }
}

int main(int argc, char** argv){
  int i;
  printf("loading libfoo. and works well");
  load_and_call("libfoo/libfoo.bundle");

  printf("loading libbar. and binding other function");
  load_and_call("libbar/libbar.bundle");
  return 0;

}