# 
# cat coroutines.c

/* Coroutines */

#include <setjmp.h>

struct coroutine
{
    jmp_buf *calling;
    jmp_buf *env;
};

#if 0
int start_coroutine (struct coroutine *cr,
    int (*f) (void *p, struct coroutine *cr),
    void *p, int *stack)
{
int x, y;
struct coroutine calling;
    x = setjmp (*(cr->calling));
    if (x == 0)
    {
        calling.calling = cr->env;
        calling.env = cr->calling;
        /* _SP = stack; */
        y = (*f) (p, &calling);
    }
    else
        return x;
}
#endif

int call_coroutine (struct coroutine *cr, int entree)
{
int x;
    x = setjmp (*(cr->calling));
    if (x == 0)
    {
        _longjmp (*(cr->env), entree);
        printf ("Error calling coroutine\n");
    }
    else
        return x;
}

int coroutine1 (char *p, struct coroutine *calling)
{
int x;
    printf ("Lancement coroutine avec parametre <%s>\n", p);
    x = call_coroutine (calling, (int)"1er parametre coroutine->appelant");
    printf ("Appelant retourne <%s> la 1ere fois\n", x);
    x = call_coroutine (calling, (int)"2eme parametre coroutine->appelant");
    printf ("Appelant retourne <%s> la 2eme fois\n", x);
    x = call_coroutine (calling, (int)"3eme parametre coroutine->appelant");
}

test_coroutine ()
{
struct coroutine cr;
jmp_buf calling, env;
#define STACK_SIZE 1000
int stack[STACK_SIZE];
int x;
    cr.calling = &calling;
    cr.env = &env;
    x = start_coroutine (&cr, coroutine1, (int)"Parametre lancement",
            stack + STACK_SIZE);
    printf ("Lancement retourne <%s>\n", x);
    x = call_coroutine (&cr, (int)"1er appel");
    printf ("1er appel retourne <%s>\n", x);
    x = call_coroutine (&cr, (int)"2eme appel");
    printf ("2eme appel retourne <%s>\n", x);
}

main ()
{
    test_coroutine ();
}

# ed coroutines.c
1671
/main
main ()

{

    test_coroutine ();

}


1

/STACK
#define STACK_SIZE 1000
/
int stack[STACK_SIZE];
s/]/+50]
int stack[STACK_SIZE+50];
w
1674
q
# cc -c -g coroutines.c
ccom: Warning: coroutines.c, line 63: & before array or function: ignored
          cr.calling = &calling;
      -------------------------^
ccom: Warning: coroutines.c, line 63: illegal pointer combination
          cr.calling = &calling;
      -------------------------^
ccom: Warning: coroutines.c, line 64: & before array or function: ignored
          cr.env = &env;
      -----------------^
ccom: Warning: coroutines.c, line 64: illegal pointer combination
          cr.env = &env;
      -----------------^
# 
# cc -c -g coroutines.c
# ed coroutines.c      
# cat coroutines.c
# ./coroutines
# cc -o coroutines coroutines.o start_coroutine.o
#
# ./coroutines
Lancement coroutine avec parametre <Parametre lancement>
Lancement retourne <1er parametre coroutine->appelant>
Appelant retourne <1er appel> la 1ere fois
1er appel retourne <2eme parametre coroutine->appelant>
Appelant retourne <2eme appel> la 2eme fois
2eme appel retourne <3eme parametre coroutine->appelant>
#   telnet rs6000