dlopen from a child process to access parent process functions

[Ravindra Jejurikar]

Hello,
    I would like a child process to have access to the parent process's functions using dlopen(). Is this possible? 

With the below code, foo() cannot be resolved. 
(It is working - foo() can be resoved -  when all code is in a single binary (instead of two as below))

dlmain.c
#include<stdio.h>

int main()
{
    printf("Hello Main: \n");
    system("dlsample");
} 


int foo(int num) {
   printf("Hello foo\n");
}

-------------------------------------------------------------
dlsample.c

typedef int (*ptrFunc)(int);

main()
   char * errstr = NULL;     
   int mode = RTLD_NOW | RTLD_PARENT | RTLD_GLOBAL ;
   void * lh = NULL;
   char * symname = "foo"; 
   ptrFunc func = NULL;  
   printf("Hello WOrld\n");

   // Open the GLOBAL executing object namespace
   lh = dlopen(NULL, mode);
   if (lh == NULL) {printf("Failed to dlopen()\n");return(1);}

   // Find the function symbol
   func = dlsym(lh, symname);
   errstr = dlerror();
   if (errstr) {printf("Error: \"%s\" in resolving symbol\n",  errstr);return(1);}
   if (func == NULL) {printf("Failed to resolve %s", symname);return(2);}

   printf("Symbol %s found at %d\n", symname, func);
   (*func)(10);
   return(0);
}

FYI: linking as below 
  gcc -Wl,-export-dynamic -o dlsample dlsample.o 

Reason to have two binaries: Eventually, I want to call some perl code from the C code and the perl code should be able to access some C functions. So I am trying with two different C binaries to start with. 

Is there an easier way to do what I am trying. I cannot have my perl code as the master with the C code as a .so (complex legacy C code - in short)

Thank you