Segmentation Fault in Fiber/Context Switching when Omitting exit(0) from Function

Question

I'm working on a context switching example using fibers in C++, and I've encountered a segmentation fault when I removed the exit(0) call from my foo function. The foo function is executed within a specific context, and it appears that without exit(0), the program encounters issues.

#include "context.hpp"
#include <iostream>
#include <cstdlib>

using namespace std;

void foo()
{
    cout << "You called foo" << endl;
    //exit(0);
}

int main()
{
    // Allocate space for stack
    char data_foo[4096];

    // Align the stacks to 16 bytes
    char *sp_foo = data_foo + sizeof(data_foo);
    sp_foo = reinterpret_cast<char*>(reinterpret_cast<uintptr_t>(sp_foo) & -16L);
    sp_foo -= 128;

    // Create contexts for foo
    Context c_foo

    // Set RIP (Register Instruction Pointer) and RSP (Register Stack Pointer) for foo
    c_foo.rip = (void*)foo;
    c_foo.rsp = sp_foo;

    // Call set_context with c_foo
    set_context(&c_foo);

    cout << "Back in main after calling foo" << endl;

    return 0;
}

I understand that exit(0) terminates the entire process, but I'm trying to comprehend why its absence leads to a segmentation fault. What are the key factors I should consider in the absence of exit(0) that might cause such issues with context switching or fibers? How does the termination of a fiber/context impact the program's state, and what precautions should be taken when not using exit?