threeFibers

#include <ucontext.h>
#include <malloc.h>
#include <stdio.h>

#define FIBER_STACK 1024*64

ucontext_t uctx_func1,uctx_func2, uctx_func3, uctx_main;

void firstFiber(){
    printf("Fiber1: started\n");
    printf("Fiber1: Now swap context to fiber2\n");
    swapcontext(&uctx_func1, &uctx_func2);
    printf("Fiber1: returned\n");
    printf("Fiber1: Now swap context to fiber2 again\n");
    swapcontext(&uctx_func1, &uctx_func2);
}
void secondFiber(){
    printf("Fiber2: started\n");
    printf("Fiber2: Now swap context to fiber3\n");
    swapcontext(&uctx_func2, &uctx_func3);
    printf("Fiber2: returned\n");
    printf("Fiber2: Now swap context to fiber3 again\n");
    swapcontext(&uctx_func2, &uctx_func3);

}
void thirdFiber(){
    printf("Fiber3: started\n");
    printf("Fiber3: Now swap context to fiber1\n");
    swapcontext(&uctx_func3, &uctx_func1);
    printf("Fiber3: returned\n");
    printf("Fiber3: Now swap context to fiber1 again\n");
    swapcontext(&uctx_func3, &uctx_main);
}

int main(){
    getcontext(&uctx_func1);
    uctx_func1.uc_link = NULL;
    uctx_func1.uc_stack.ss_sp = malloc(FIBER_STACK);
    uctx_func1.uc_stack.ss_size = FIBER_STACK;
    uctx_func1.uc_stack.ss_flags = 0;
    makecontext(&uctx_func1, firstFiber, 0);

    getcontext(&uctx_func2);
    uctx_func2.uc_link = NULL;
    uctx_func2.uc_stack.ss_sp = malloc(FIBER_STACK);
    uctx_func2.uc_stack.ss_size = FIBER_STACK;
    uctx_func2.uc_stack.ss_flags = 0;
    makecontext(&uctx_func2, secondFiber, 0);

    getcontext(&uctx_func3);
    uctx_func3.uc_link = NULL;
    uctx_func3.uc_stack.ss_sp = malloc(FIBER_STACK);
    uctx_func3.uc_stack.ss_size = FIBER_STACK;
    uctx_func3.uc_stack.ss_flags = 0;
    makecontext(&uctx_func3, thirdFiber, 0);


    printf("Main: swap context to fiber1\n");
    swapcontext(&uctx_main, &uctx_func1);




    printf("Main: returned\n");
    printf("Main: exiting\n");

    return 0;
}