Question

I am new to threads and processes.

I have code that works fine right now with forking the code into multiple processes. However each process needs to add to a global variable, but from what I read, each time the process forks, it takes a copy of the global, and adds them independently. Is there a way to join them, like you can with threads?

Answer 1

Different processes can communicate and exchange data via shared memory.
On linux, you can look:

man shm_overview

for attaching a memory segment on several processes

and

man sem_overview
for the semaphore library for controlling parallel access.