when I fork, I have a problem with setting a variable in the main parent loop and making the child process check that variable even though I am passing a reference to the variable in the child proces

References always refer to addresses in the process's own memory spaces. Each process has its own memory space, and one process cannot access the memory space of another process. When the child dereferences a reference, it's accessing the copy of the referenced variable in the child's memory space and not to a variable in the parent's memory space.