Question

Suppose I have a main process running and in its execution it has initialized some pointers and created some instances of a predefined structure.

Now if I fork this main process, is seperate memory allocated for the pointers?And are duplicate instances of the previously existing variables, data structures created for this new process?

As an example of my requirement consider –

struct CKT
{
  ...
}

main()
{
   ...Some computations with the structure and other pointers.....
   pid_t pid = fork();
   if(pid == 0) //child
   {
       ..some more computations with the structure...but I need a 
       ..separate instance of it with all the pointers in it as well..
   }
   else if(pid > 0) // parent
   {
       ..working with the original instance of the structure..
   }
   // merging the child process with the parent...
   // after reading the data of the child processes structure's data... 
   // and considering a few cases...
}

Can anyone explain how do I achieve this??

Answer 1

pointer and memory content both will be duplicated for the fork child.

all kind of data pointers, memory, variable will be duplicate in a separate memory for the child process created with fork. and you could not change pointers neither memory content from process child directly.

but you can change variable of parent process from child process using memory share

Refer to this link to see how to it: How to share memory between process fork()?