coroutine sample @ hedgezzz的部落格

sample from https://gist.github.com/felipec/13493

#ifndef TRANS_H
#define TRANS_H

#include <ucontext.h>

#include <stdbool.h>
#include <stdio.h>

struct task
{
    bool pending;
    char stack[SIGSTKSZ];
    int  icnt ;
    ucontext_t context;
    ucontext_t main_context;
};

typedef void (*task_func) (struct task *t);

static inline struct task *
task_new (task_func func)
{
    struct task *t;

    t = calloc (sizeof (struct task), 1);

    getcontext (&t->context);

    t->context.uc_link = 0;
    t->context.uc_stack.ss_sp = t->stack;
    t->context.uc_stack.ss_size = sizeof (t->stack);
    t->context.uc_stack.ss_flags = 0;

    makecontext (&t->context, (void (*)()) func, 1, t);

    swapcontext (&t->main_context, &t->context);

    return t;
}

static inline void
task_free (struct task *t)
{
    free (t);
}

static inline void
task_yield (struct task *t)
{
    t->pending = true;
    swapcontext (&t->context, &t->main_context);
}

static inline void
task_complete (struct task *t)
{
    t->pending = false;
    swapcontext (&t->context, &t->main_context);
}

static inline void
task_handle (struct task *t)
{
    if (t->pending)
        swapcontext (&t->main_context, &t->context);
}

static inline void
task_inc_icnt(struct task *t)
{
++t->icnt ;
}

static inline int
task_print_icnt(struct task *t)
{
return t->icnt ;
}

#endif /* TRANS_H */

===================================================

#include "task.h"

void func(struct task* t)
{
    int idx ;
    printf("inside func \n") ;
    for(idx=0;idx<5;idx++)
    {
        printf("(%d)....\n",idx) ;
        task_inc_icnt(t) ;
        task_yield(t) ;
    }
    task_complete(t) ;
}

int main (int argc, char *argv[])
{
    task_func f = &func ;
    struct task* t ;
    t = task_new(f) ;
    printf("after task_new \n") ;
    int idx ;
    for(idx=0;idx<10;idx++)
    {
        printf("in main \n") ;
        task_handle(t) ;
    }
    printf("icnt=(%d)\n",task_print_icnt(t)) ;
    task_free(t) ;
    printf("end \n") ;
}

=====================================================

inside func
(0)....
after task_new
in main
(1)....
in main
(2)....
in main
(3)....
in main
(4)....
in main
in main
in main
in main
in main
in main
icnt=(4)
end