It's easy to load functions from dynamic libraries when you know this function in design time. just do something like this:

   int (*fn)(int);

   l0 = dlopen("./libfoo.so", RTLD_LAZY);
   if (!l0) 
   {
      fprintf(stderr, "l0 %s\n", dlerror());
      return 1;
   }


   fn = (int (*)(int))dlsym(l0, "foo");


   if ((error = dlerror()) != NULL)  
   {
      fprintf(stderr, "fn:%s\n", error);
      return 1;
   }

   x=(*fn)(y);

...

How to execute library function when it's unknown in design time? In runtime you have a function name and array of arguments pointers and array of arguments sizes:

char* fn_name="foo"; int foo_argc; void* foo_argv[]; int foo_argv_size[];

In scripting language it's a piece a cake task, but how to implement this nicely in c++?